Balochistan Mdcat Mock Paper 2 — Solved Past Paper with Answers

Q1. Choose the correct spelling of the word:

• A. Something✓
• B. Somthing
• C. Sumthing
• D. Sumthin

Explanation: The correct spelling is 'something'.

Q2. Select the option which fits appropriately in the blank: It will _ me a lot of money.

• A. Costs
• B. Cost✓
• C. Costed
• D. Is costing

Explanation: The presence of the word "will" indicates that this is a sentence of the future tense. Hence, the word "cost" will be the best word to use here.

Q3. Select the option which fits appropriately in the blank: Annie and her brothers _ at school.

• A. Is
• B. Are✓
• C. Are being
• D. Have

Explanation: When deciding whether to use 'is' or 'are', look at whether the noun is plural or singular. If the noun is singular, use 'is'. If it is plural or there is more than one noun, use 'are'. Here the noun is plural (brothers) hence, the correct option is 'are'.

Q4. Select the option which fits appropriately in the blank: My father often _ here.

• A. Come
• B. Came
• C. Comes✓
• D. Coming

Explanation: 'Comes' is the singular present tense of the word 'come' so it will be used here as the father is coming to the location presently.

Q5. Select the option which fits appropriately in the blank: Dan _ a lot of friends.

• A. Have
• B. Has✓
• C. Is having
• D. Having

Explanation: 'Has' is the third person singular present tense of 'is' and it will be used as the term friends is plural, so the verb must be singular.

Q6. Select the option which fits appropriately in the blank: We shall _ there for a week.

• A. Be going✓
• B. Has been gone
• C. Has going
• D. Been going

Explanation: The expression 'be going' allows us to express an idea in the near future.

Q7. There was _ article about pollution in _ paper.

• A. A..an
• B. An...the✓
• C. A...the
• D. A...a

Explanation: A/an and the are articles. They are types of determiners and they go before a noun. Use “a” before words that start with a consonant sound and “an” before words that start with a vowel sound. The definite article is used before singular and plural nouns when the noun is specific or particular. The signals that the noun is definite, that it refers to a particular member of a group. For example: 'The dog that bit me ran away.' Here, we're talking about a specific dog, the dog that bit me.

Q8. Which verb is NOT in the present tense?

• A. She listened✓
• B. She talks
• C. She waits
• D. She eats

Explanation: The presence of -ed creates a past tense in the sentence. talks" is in the present tense, describing an action that is currently happening. "waits" is in the present tense, describing an ongoing action or state. "eats" is also in the present tense, describing a habitual or repeated action.

Q9. Sameer _ in the park every day.

• A. Run
• B. Runs✓
• C. Running
• D. Walk

Explanation: Run - This is the base form of the verb, but it does not agree with the subject "Sameer" because it is not in the third-person singular form. Therefore, this is not the correct answer.Runs - 3rd person singular present tense of run is runs. Running - This is the present participle form of the verb. While it is grammatically correct, it does not fit in the sentence structure as it cannot be used as the main verb of the sentence.Walk - This is a completely different verb and does not agree with the subject "Sameer" in the sentence. Therefore, this is not the correct answer.

Q10. My parents _ near Lahore.

• A. Living
• B. Are living
• C. Lives
• D. Live✓

Explanation: Option A : "Living near" is incorrect as it does not agree with the subject-verb agreement.Option B : "Are living" is also incorrect as it uses the present continuous tense, which is not suitable for describing a present state.Option C : "Lives" is incorrect as it is in the third-person singular form, which does not agree with the subject "my parents," which is in the plural form Parents is a plural noun so the verb used should be singular.

Q11. Sumafra was surprised when her boss didn't _ the dinner that they had at the restaurant.

• A. Buy
• B. Pay
• C. Pay for✓
• D. Spend

Explanation: "Buy" is not the best answer because it is not clear what Sumafra's boss would have bought. Moreover, the context suggests that they have already eaten at the restaurant."Pay" could be a possible answer, but it is not specific enough. "Pay" could mean paying for something else or settling a previous debt, so it is less accurate than option C. 'For' must be used when the reason or purpose is a noun. "Spend" is not a suitable answer because it does not specify who is spending the money. Additionally, it is not clear what the money is being spent on.

Q12. Find the error in the following sentence: "Even if the doctor puts in his best efforts, he could not succeed in saving the patient."

• A. Even if the doctor✓
• B. Put in his best efforts, he
• C. Could not succeed in
• D. Saving the patient.

Explanation: Instead of 'even' it should be 'although'. "Although the doctor put in his best effort, he could not succeed in saving the patient."

Q13. I like _ blue T-shirt over there better than _ red one.

• A. A...a
• B. A...an
• C. The...a
• D. The...the✓

Explanation: The definite article is used before singular and plural nouns when the noun is specific or particular. 'The' signals that the noun is definite, and that it refers to a particular member of a group.

Q14. Choose the nearest meaning to the following word: Relinquish

• A. Use
• B. Surrender✓
• C. Increase
• D. Retain

Explanation: Relinquish means to voluntarily cease to keep or claim; give up so 'surrender' makes a suitable synonym.

Q15. You will find more information in the _.

• A. Attached to file
• B. Attached file✓
• C. Attachment file
• D. File what is attached

Explanation: The file will be described with the adjective 'attached'. Because the file was uploaded and attached previuosly, hence we will use attached which indicated a past tense sentence. If you're using a document to reiterate a point or idea in an email, mentioning the attached file will keep your reader focused on the key takeaway.

Q16. Choose the option with the nearest meaning to the following word: Waft

• A. Wave
• B. Drift✓
• C. Stump
• D. Keep

Explanation: For something to waft is for it to pass or cause to pass gently through the air.

Q17. What type of sentence is this? When I go swimming, I have to keep my eyes closed underwater.

• A. Complex✓
• B. Simple
• C. Compound
• D. None

Explanation: A complex sentence is formed by adding one or more subordinate (dependent) clauses to the main (independent) clause using conjunctions and/or relative pronouns.

Q18. According to the fluid mosaic model of cell membrane, which zone is embedded inside?

• A. Hydrophobic✓
• B. Hydrophilic
• C. Globular
• D. Filamentous

Explanation: The fluid mosaic model describes the cell membrane as a tapestry of several types of molecules (phospholipids, cholesterols, and proteins) that are constantly moving. This movement helps the cell membrane maintain its role as a barrier between the inside and outside of the cell environment. Phospholipids, arranged in a bilayer, make up the basic fabric of the plasma membrane. They are well-suited for this role because they are amphipathic, meaning that they have both hydrophilic and hydrophobic regions. Since the outer region of the cell membrane comes in contact with the fluid so the hydrophilic heads are present on the surface of the membrane while the hydrophobic tails are embedded inside the membrane. The diagram below represents this model.

Q19. Tissue is a

• A. group of cells✓
• B. group of organs
• C. group of tissues
• D. group of organisms

Explanation: Tissue is a group of cells that have similar structure and that function together as a unit.

Q20. Suggest which among the following is not a function attributed to endoplasmic reticulum?

• A. Detoxification of poisons and drugs
• B. Digestion/egestion of foreign materials outside the cell✓
• C. Manufacture of fat and lipid molecules
• D. Biogenesis of membrane proteins

Explanation: The endoplasmic reticulum is involved in the detoxification of the poisons and the drugs. This is the main function of the endoplasmic reticulum in the liver. The manufacturing of the lipids and fat molecules take place in the smooth ER. The membrane proteins are synthesised on the ribosomes which are present on the surface of the ER. The digestion and egestion of the foreign materials which enter the cells take place in the lysosomes. Thus, the correct answer is option B.

Q21. Which of the following cell organelles involved in the synthesis of cell wall and middle lamella?

• A. Endoplasmic reticulum
• B. Golgi apparatus✓
• C. Lysosomes
• D. Peroxisomes

Explanation: The Golgi and plasma membranes are the two main sites where constituents of cell wall are synthesized. The Golgi body is also known as Golgi apparatus. It synthesizes vesicles which then fuse to form the middle lamella as shown below.

Q22. Which property of water helps to maintain the integrity of lipid-containing membranes?

• A. Specific Heat Capacity
• B. Hydrogen Bonding
• C. Cohesion and Adhesion
• D. Hydrophobic exclusion✓

Explanation: If you place a few drops of oil on the surface of a water solution, the oil drops will tend to coalesce (to unite into one whole) into a single drop. Biologically, hydrophobic exclusion plays a key role in maintaining the integrity of lipid bilayer membranes due to the hydrophobic tails of the phospholipid molecules. Tails of two layers of phospholipids interact to form a hydrophobic internal center of cell membranes while the phospholipid heads interact with the hydrophilic water medium externally. This is shown below.

Q23. In which step is lysozyme released by the bacteriophage?

• A. Attachment
• B. Penetration✓
• C. Injection
• D. Replication

Explanation: Lysozyme is a digestive enzyme so it will have to be released when the bacterial cell wall has to be digested which occurs during the process of 'penetration'.

Q24. Most reflex arcs are:

• A. Monosynaptic reflex
• B. Polysynaptic reflex✓
• C. Hemi Synaptic Reflex
• D. None of these

Explanation: Most reflex arcs are 'polysynaptic', meaning multiple interneurons (also called relay neurons) interface between the sensory and motor neurons in the reflex pathway.

Q25. Nitrogenous bases such as choline and serine are a significant part of which of the following?

• A. Sphingolipids
• B. Phospholipids✓
• C. Phosphodiester
• D. None of these

Explanation: These nitrogenous bases can combine with 'phospholipids' to form phosphatidylcholine and phosphatidylserine respectively.

Q26. The wings of a bird and the wings of a beetle are considered?

• A. Taxonomic
• B. Phylogenetic
• C. Homologous
• D. Analogous✓

Explanation: Birds and beetles belong to two different groups of animals Beatles an insects and birds are not insects. The wings of both these animals perform the same function which is to help them fly. Since they perform the same function but have a different origin they are considered to be called analogous organs.

Q27. The voice box leads to the trachea which is also called

• A. Bronchi
• B. Bronchioles
• C. Windpipe✓
• D. Alveolar duct

Explanation: Another name of the trachea is the 'windpipe'.

Q28. Sycon is an example of:

• A. Platyhelminthes
• B. Annelids
• C. Protozoa
• D. Porifera✓

Explanation: Sycon is an example of Porifera. Porifera is a phylum of animals that are also known as sponges. Sponges are simple animals that do not have a body cavity or organs. They are filter feeders, meaning that they obtain their food by filtering water through their bodies.

Q29. The attraction between water molecules and cell wall of xylem is termed as:

• A. Cohesion
• B. Tension
• C. Adhesion✓
• D. Imbibition

Explanation: Adhesion is the tendency of dissimilar particles or surfaces to cling to one another. It's the force of attraction that causes different substances to stick together. Adhesion is the opposite of cohesion, which refers to the tendency of like particles or surfaces to stick together.Water molecules exhibit adhesion when they "stick" to other surfaces, such as the walls of a tube or the surface of a solid. Adhesion, along with cohesion, contributes to capillary action, where liquids move against gravity in narrow spaces. It also influences the behavior of liquids in containers, such as meniscus formation in a graduated cylinder.

Q30. Cellular organelles that interact with hydrogen peroxide are called?

• A. Glyoxysomes
• B. Lysosomes
• C. Ribosomes
• D. Peroxisomes✓

Explanation: De-Duve and coworkers isolated 1965 particles from liver cells and other tissues that were enriched with some oxidative enzymes, such as peroxidase, catalase, glycolic acid oxidase, and some other enzymes. The name peroxisome was applied because this organelle is specifically involved in the formation and decomposition of hydrogen peroxide in the cell. These are single membrane-enclosed cytoplasmic organelles found both in animal and plant cells. These are characterized by containing H202-producing oxidases and catalase. They are approximately 0.5 nm in diameter. They have also been found in protozoa, yeast, and many cell types of higher plants.

Q31. What is the name of the tube that carries sperm and urine out of the human body?

• A. Penis
• B. Urethra✓
• C. Seminal vesicles
• D. Ureter

Explanation: Explanation for this question will be added soon.

Q32. Example of bacteria requiring low concentration of oxygen is?

• A. Spirochete
• B. Seudomonas
• C. E.coli
• D. Campylobacter✓

Explanation: Campylobacter is a genus of bacteria that are mostly microaerophilic, i.e. they require a very low concentration of oxygen to survive. At higher concentrations, these can not survive.

Q33. Which among the following is a diploblastic organism?

• A. Hydra✓
• B. Squid
• C. Earthworm
• D. Crabs

Explanation: Hydra belongs to phylum Cnidaria which is the only diploblastic phylum i.e., its embryo contains only two germ layers; the endoderm and ectoderm connected by a gel-like mesoglea.

Q34. After fertilisation the zygote increases in size and travels down the Fallopian tube to become embedded in the walls of the womb. This process is called:

• A. Ovulation
• B. Implantation✓
• C. Conception
• D. Menstruation

Explanation: Implantation is the process of the zygote increasing in size and embedding itself into the walls of the endometrium.

Q35. Inheritance in man is traced by which of the following?

• A. Mathematical method
• B. Pedigree method✓
• C. Statistical method
• D. Genetic method

Explanation: A pedigree is a genetic representation of a family tree that diagrams the inheritance of a trait or disease through several generations. The pedigree shows the relationships between family members and indicates which individuals express or silently carry the trait in question.

Q36. Water acts as a universal solvent because of:

• A. Heat of vaporization
• B. Hydrogen bonding
• C. High polarity✓
• D. Cohesion and adhesion

Explanation: Water is called the "universal solvent" because it dissolves more substances than any other liquid. Because of its polarity, the water molecule becomes attracted to many other different types of molecules. Hydrogen mainly comes into the discussion for water's high boiling and melting point, alongside its interaction with other molecules capable of making hydrogen bonds. Since this excludes the dissolution of polar substances such as ions, etc. hydrogen bonding alone does not explain the Universal dissolution of water. Water also has a high heat of vaporization which is the amount of energy needed to change one gram of a liquid substance to gas at a constant temperature. However, that property doesn't make water suitable to be the 'universal solvent'. Moreover, In humans and other organisms, the evaporation of sweat, which is about 99% water, cools the body to maintain a steady temperature. The ability of Cohesion (Water molecules are attracted to each other) and Adhesion (Water is attracted to other substances) also doesn't make it worthy to be called the 'universal solvent'.

Q37. Lipids store double the amount of energy as compared to carbohydrates because of:

• A. High proportion of oxygen
• B. High C-O ratio
• C. Low proportion of Carbon
• D. High proportion of C-H✓

Explanation: The normal oxidative process yields approximately 9 kcal per gram of fats, and approximately 4 kcal per gram for carbohydrates. Lipids are generally more “fully reduced” from a chemical perspective as they have significantly more C-C and C-H bonds and the energy is stored within these bonds. Under a normal oxidative process, these bonds are broken in the presence of oxygen to yield carbon dioxide, water, and energy (exothermic reaction).

Q38. Which of the following is an unsaturated fatty acid?

• A. Oleic acid✓
• B. Palmitic acid
• C. Butyric acid
• D. Acetic acid

Explanation: Unsaturated fatty acids have one or more carbon-carbon double bonds. The term unsaturated indicates that fewer than the maximum possible number of hydrogen atoms are bonded to each carbon in the molecule. Oleic acid is an example of a monounsaturated fatty acid as it has only a single double bond present in the long chain of carbons bonded to each other.Butyric acid (butanoic acid) is a 4-carbon saturated carboxylic acid. Acetic acid (ethanoic acid) is a carbon-2 saturated carboxylic acid. Palmitic acid is a 16-carbon saturated carboxylic acid.

Q39. Mono-saccharides have a general formula represented by:

• A. (CH2O)n✓
• B. C(H2O)n
• C. C2(H2O)n
• D. C2(H2O)n

Explanation: A monosaccharide is the most basic form of carbohydrates. Monosaccharides can be combined through glycosidic bonds to form larger carbohydrates, known as oligosaccharides or polysaccharides. The general formula for Mono-saccharides is (CH2O)n. Note that A and B are NOT the same. A is made up of n carbon atoms and n H₂O molecules. B is made up of 1 carbon atom and n molecules of H₂O.

Q40. What is the function of the lysozyme enzyme released by bacteriophages?

• A. Injecting DNA
• B. Replication
• C. Dissolve bacterial cell wall✓
• D. All of these

Explanation: The lysozyme enzyme is a digestive enzyme that 'digests the bacterial cell wall'.

Q41. The function of a cell wall in prokaryotes is:

• A. To give cells rigidity
• B. To give specific shape
• C. To protect from osmotic lysis
• D. All of Above✓

Explanation: All prokaryotic cells have a stiff cell wall located underneath the capsule (if there is one). This structure maintains the 'cell's shape', protects the cell interior, and prevents the cell from bursting when it takes up water. Since the bacterial cell wall is 'thick and rigid', it will maintain the shape of the cell and also 'protect it from osmotic lysis' just like the cell wall of plants. Hence, the correct option is 'D'.

Q42. How many monosaccharide molecules do oligosaccharides yield upon hydrolysis?

• A. 2
• B. 5
• C. 10
• D. All of these✓

Explanation: 'Oligosaccharides' are carbohydrates that contain carbon atoms ranging from 'two to ten' monosaccharides and hence, upon hydrolysis can give any number of monosaccharides from 2 to 10.

Q43. Carotenoids perform protective function in which of the following organism?

• A. Animals
• B. Plants
• C. Both✓
• D. None of these

Explanation: Carotenoids perform a protective function in plants. They act as pigments and antioxidants, helping to protect plant cells from damage caused by excessive light and reactive oxygen species. Moreover, carotenoid pigments, present in many eyes and photoreceptors, seem especially suited to protect against the deleterious effects of light because they absorb the dangerous short wavelength part of the light spectrum. Hence correct option is option C.

Q44. The dense fluid filled region in the chloroplast is?

• A. Grana
• B. Stroma✓
• C. Thylakoid
• D. Intergrana

Explanation: Option A: Grana: Stacks of thylakoids within the chloroplast responsible for the light-dependent reactions of photosynthesis. Option B: The stroma is the dense fluid-filled region within the chloroplast, surrounding the thylakoid membranes. It plays a crucial role in various metabolic processes, including the synthesis of organic molecules through photosynthesis. Option C: Thylakoid: Flattened disc-like structures within the chloroplast containing photosynthetic pigments and responsible for capturing light energy. Option D: Intergrana: Not a recognized term; it may refer to the spaces or regions between the grana or thylakoid membranes, but the more accurate term is stroma lamellae.

Q45. What is the most important structure between body and brain?

• A. Neck
• B. Spinal cord✓
• C. Blood vessels
• D. Skeleton

Explanation: The explanation for this question is as follow: The spinal cord is the centre for great many reflexes and it serves as a pathway for conduction of impulses to and from different parts of the body and brain.Messages from the body and the brain run up and down the spinal cord, the body's information highway.

Q46. At what times is there a no net gaseous exchange between leaves and the atmosphere?

• A. Day
• B. Night
• C. Dawn and Dusk✓
• D. Midnight

Explanation: Option A: During the daytime, photosynthesis is actively taking place in the presence of sunlight. This process involves the intake of carbon dioxide and release of oxygen, leading to a net exchange of gases between leaves and the atmosphere.Option B: During nighttime, photosynthesis ceases as there is no sunlight available for the process. In the absence of photosynthesis, plants primarily engage in respiration, consuming oxygen and releasing carbon dioxide. This results in a net exchange of gases, where more carbon dioxide is released than oxygen is produced.Option C: At the time of dawn and dusk there is no net gaseous exchange between leaves and atmosphere. At dawn and dusk,when light intensity is low, the rate of photosynthesis and respiration may, for a short time, equal one another. Thus the oxygen released from photosynthesis is just the amount required for cellular respiration. Also, the carbon dioxide released by respiration just equals the quantity required by photosynthesizing cells. At this moment there is no net gas exchange between the leaves and the atmosphere. This is termed as compensation point. Option D: Midnight refers to the middle of the night when it is typically dark, and plants primarily undergo respiration. Similar to nighttime, there is a net release of carbon dioxide and consumption of oxygen during this period.

Q47. Identify the characteristic of acoelomates.

• A. Absence of mesoderm
• B. Absence of brain
• C. Coelom that is incompletely lined with a mesoderm
• D. Solid-body without a cavity surrounding internal organs✓

Explanation: Acoelomates lack a coelom (neither true nor false/pseudocoelom). Hence they lack a cavity surrounding internal organs and have a solid body.

Q48. The nervous system of nematodes consists of which of the following;

• A. Ventral nerve cord
• B. Lateral nerve cord
• C. Dorsal nerve cord
• D. All of these✓

Explanation: The nervous system of nematodes (roundworm/ascehelmintus) comprises of a ring of nervous tissue beneath the pharynx and four longitudinal nerve cords corresponding to the dorsal region, ventral region, and two lateral regions.

Q49. The main unit of the thick filament is:

• A. Myofibril
• B. Z-line
• C. Myosin✓
• D. Actin

Explanation: Myosin is the primary component of the thick filament.

Q50. All of the following are the current preventive methods for HIV infection, except?

• A. Safe and protected lifestyle
• B. Use of sterile injections and needles
• C. Use of available vaccines✓
• D. Safe blood transfusion methods

Explanation: There is no vaccine currently available to offer protection against AIDS caused by HIV.

Q51. Choose the region of spinal cord:

• A. Cervical
• B. Thoracic
• C. Lumbar
• D. All of these✓

Explanation: The explanation for this question is as follows: The spinal cord divides into 31 segments: cervical 8, thoracic 12, lumbar 5, sacral 5, and coccygeal 1. These segments consist of 31 pairs of spinal nerves with their respective spinal root ganglia. Spinal nerves contain the motor, sensory, and autonomic fibers. These nerves exit through the intervertebral foramen.

Q52. The fluid mosaic model of plasma membrane proposes that membranes are:

• A. Solid
• B. Semi-solid✓
• C. Fluid
• D. Liquid

Explanation: The semi-solid consistency of the plasma membrane is due to the interaction of the phospholipids in the bilayer and the proteins embedded in the bilayer. The phospholipids are constantly moving and changing their positions, but they are also held together by weak interactions. This allows the plasma membrane to be flexible and to change shape, but it also prevents the membrane from becoming too fluid.

Q53. NAD is an example of:

• A. Mononucleotide
• B. Dinucleotide✓
• C. Trinucleotide
• D. Tetranucleotide

Explanation: Nicotinamide adenine dinucleotide (NAD) is a cofactor central to metabolism. Found in all living cells, NAD is called a dinucleotide because it consists of two nucleotides joined through their phosphate groups. The cellular respiration processes of all living cells make use of the coenzyme Nicotinamide adenine dinucleotide (NAD). It plays a key role in energy metabolism by accepting and donating electrons. The low energy form NAD+, shown at left, is raised to the high energy form 'NADH'.

Q54. Lock and Key Model for enzyme action propose by Emil Fischer suggests that:

• A. Enzymes are unbiased for the substrate
• B. Enzymes can modify their active sites
• C. Enzymes are restricted to one reaction type✓
• D. An enzyme can catalyze variety of reactions

Explanation: The lock and key mechanism is a metaphor to explain the specificity of the enzyme's active site and the substrate. Similar to how only a certain key fits a lock, only certain substrates can fit an enzyme's active site. When the correct substrate binds to the enzyme's active site, an Enzyme substrate complex is formed. This simply means that only one type of substrate can be acted upon by an enzyme. The statement C implies that since only one type of substrate can fit into the active site of an enzyme, the type of reaction either being catabolic or anabolic in nature is also dependent on the active site of the enzyme and the type of substrate. To further explain, consider an example of an enzyme A acting on a substrate A in a catabolic reaction. It would only be able to catalyze the catabolic reaction and not any other type of reaction such as anabolic reaction on that particular substrate. A and D, on the other hand, are the exact opposite of the above statements as enzymes are specific for the substrate.

Q55. Most enzymes have an optimum temperature of around:

• A. 30°C
• B. 40°C✓
• C. 50°C
• D. 20°C

Explanation: Most enzymes have an optimum temperature at which they function most efficiently. For many enzymes in the human body, this optimum temperature is around 37 degrees Celsius (98.6 degrees Fahrenheit), which is the normal body temperature. However, the specific optimum temperature can vary for different enzymes. Hence here we will select 40 degrees Celsius.

Q56. Enzymes work by lowering the _ of the reactions they catalyse:

• A. Kinetic energy
• B. Activation energy✓
• C. Heat energy
• D. Potential energy

Explanation: Activation Energy is the minimum amount of energy that the reacting species must possess in order to undergo a specified reaction. Enzymes speed up reactions by lowering this energy and hence the reaction occurs faster by the virtue of more reactants being capable of initiating and taking part in the reaction due to the lowered energy threshold. Kinetic energy (KE) of an object is the energy that it possesses due to its motion. Heat energy is the result of the movement of tiny particles called atoms, molecules or ions in solids, liquids and gases. Potential energy is energy that is stored – or conserved - in an object or substance. This stored energy is based on the position, arrangement or state of the object or substance. You can think of it as energy that has the 'potential' to do work.

Q57. Nutrition to egg in ovary is provided by which of the following?

• A. Germ cells
• B. Milk cells
• C. Follicle cells✓
• D. All of these

Explanation: Nutrition in egg to the ovary is provided by 'follicle cells'.

Q58. Which portion of the brain is primarily responsible for transmitting the information to other parts of the nervous system?

• A. White matter✓
• B. Gray matter
• C. Medulla Oblongata
• D. All A, B and C

Explanation: The explanation for this question is as follow: White matter consists of myelinated nerve fibers, which act like the "wires" that transmit signals between different parts of the brain and the nervous system. It contains axons of neurons that connect various regions of the brain and relay information, facilitating communication between different areas of the central nervous system.

Q59. Gray matter is primarily composed of:

• A. Axons
• B. Synapse
• C. Neuron somas✓
• D. None of these

Explanation: Gray matter is primarily composed of "Neuron somas" or cell bodies. In the nervous system, gray matter refers to the regions of the brain and spinal cord where the cell bodies of neurons are densely packed. It appears gray due to the presence of cell bodies, which contain the nucleus and other organelles required for the neuron's metabolic functions and information processing. Gray matter contains various types of neurons that are responsible for processing and integrating incoming signals from sensory neurons or other areas of the brain. It plays a crucial role in cognition, sensory perception, motor control, and other higher-order brain functions.

Q60. What is the viral envelope composed of?

• A. Proteins
• B. Glycoproteins
• C. Lipids and proteins
• D. All of the above✓

Explanation: The envelopes are typically derived from portions of the host cell membranes (''phospholipids and proteins''), but include some viral 'glycoproteins'. The viral envelope is derived from the host cell so the host plasma membrane also possesses lipids, proteins, and glycoproteins. It is the viral capsid that is composed of only proteins.

Q61. During inspiration, the area of the thoracic cavity will _.

• A. Contract
• B. Increase✓
• C. Decrease
• D. Damage

Explanation: Option A: Incorrect. The muscles involved in inspiration actually contract, causing the thoracic cavity to expand. Option B: During inspiration (inhaling), the area of the thoracic cavity increases. This is achieved through the contraction of the diaphragm and the external intercostal muscles. The diaphragm moves downward and the ribcage expands as the external intercostal muscles contract. These actions result in an increase in the volume of the thoracic cavity, creating negative pressure within the lungs. This negative pressure allows air to be drawn into the lungs, facilitating the process of breathing.Option C: Incorrect. The thoracic cavity increases in size during inspiration, not decreases. Option D: Irrelevant. This option does not relate to the changes that occur during inspiration.

Q62. Antibodies can be digested by using which of the following type of enzymes?

• A. Lipase
• B. Protease✓
• C. Amylase
• D. Polymerase

Explanation: Option A: Lipase is an enzyme that primarily breaks down lipids (fats). It does not play a significant role in digesting antibodies. Option B: Protease is an enzyme that breaks down proteins into smaller peptides or amino acids. Antibodies are proteins, so proteases are capable of digesting them. Option C: Amylase is an enzyme that breaks down carbohydrates, specifically starches and glycogen. It does not have a significant role in digesting antibodies. Option D: Polymerase is an enzyme involved in DNA replication and synthesis. It is not involved in the digestion of antibodies.

Q63. This group of animals have three bones in the ear.

• A. Reptiles
• B. Mammals✓
• C. Both reptiles and mammals
• D. Birds and mammals

Explanation: Option A: Reptiles generally do not have three bones in the ear. Instead, reptiles typically have a single bone in their middle ear called the stapes or columella. This bone is responsible for transmitting sound vibrations from the eardrum to the inner ear.Option B: Mammals have three bones in the ear. These three bones, known as the ossicles, are located in the middle ear. They are named the malleus (hammer), incus (anvil), and stapes (stirrup). The ossicles transmit sound vibrations from the eardrum to the inner ear, amplifying and transmitting sound waves for auditory perception.Option C: Both reptiles and mammals: This option is incorrect. Reptiles typically have a single bone (stapes or columella) in the middle ear, while mammals have the three ossicles (malleus, incus, and stapes).Option D: Birds and mammals: This option is correct. Both birds and mammals have three bones in the ear. In birds, the three bones are called the columella, incus, and stapes. These bones play a similar role to the mammalian ossicles, transmitting sound vibrations from the eardrum to the inner ear for auditory processing.

Q64. The functional parts of forebrain are:

• A. Thalamus and limbic system
• B. Cerebrum, limbic system and thalamus✓
• C. Thalamus and cerebrum
• D. Cerebrum and limbic system

Explanation: Forebrain is the limbic system, thalamus and the cerebrum

Q65. Which of the following is NOT a function of Smooth Endoplasmic Reticulum (SER)?

• A. Detoxification of harmful drugs.
• B. Synthesis of phospholipids for plasma membrane.
• C. Synthesis of membrane proteins.✓
• D. Synthesis of steroid hormones from cholesterol.

Explanation: Protein synthesis is a function of the rough endoplasmic reticulum and not of the smooth endoplasmic reticulum.

Q66. Which statement correctly describes, why ions are unable to cross the plasma membrane without channel proteins?

• A. They are unable to cross the hydrophilic phosphate heads of the lipid bilayer.
• B. They are unable to cross the hydrophobic tails of the lipid bilayer.✓
• C. They are unable to cross both the phosphate heads and fatty acid chains of the lipid bilayer.
• D. They are too big to cross the plasma membrane.

Explanation: Ions being are hydrophilic in nature and so are repelled by the hydrophobic interior of the plasma membrane which consists of hydrophobic fatty acid chains. This prevents the ions from freely crossing the membrane without any channel or carrier proteins.

Q67. Which of the following is a function of endoplasmic reticulum?

• A. Transport of molecules
• B. Mechanical support
• C. Conjugated molecules synthesis
• D. All of these✓

Explanation: The endoplasmic reticulum allows the transport of material in the cell and the synthesis of conjugated molecules (glycoproteins). The membranes of ER act as an ultrastructural skeletal framework in the cell and provide mechanical support.

Q68. First stable compound during Calvin cycle is:

• A. 3-phosphoglycerate✓
• B. Glyceraldehyde 3 - phosphate
• C. 1, 3 bisphosphoglycerate
• D. Ribulose bisphosphate

Explanation: The first stable compound in the Calvin cycle is a 3 carbon compound namely 3 phosphoglyceric acid (PGA). Hence the Calvin cycle is also called as C3 cycle. This compound is produced by carbon dioxide fixation reaction catalyzed by ribulose 1, 5 bisphosphate carboxylase/ oxygenase (RUBISCO) enzyme, which carboxylates one molecule of five carbon atom-containing compound, ribulose 1, 5 bisphosphate (RUBP) into two molecules of the three carbon atom-containing compound 3 PGA.

Q69. What is the function of Ribulose?

• A. Intermediates in photosynthesis✓
• B. Respiratory fuel
• C. Intermediates in cellular respiration
• D. Component of DNA and RNA

Explanation: Ribulose bisphosphate carboxylase/oxygenase (rubisco) is a key enzyme in photosynthesis, catalyzing carbon dioxide fixation. Rubisco is ubiquitous for photosynthetic organisms and is regarded as the most abundant protein on earth. It catalyzes the formation of organic molecules from CO2.

Q70. Which of the following processes does NOT need Pyruvic Acid as a substrate?

• A. Alcoholic fermentation
• B. Calvin cycle✓
• C. Aerobic respiration
• D. Lactic Acid fermentation

Explanation: Calvin cycle does not require pyruvate rather just requires RuBP and CO2 for carbon dioxide fixation, as shown by the diagram below. All other reactions mentioned in other options do require pyruvate.

Q71. In 1959, Koshland proposed which of the following?

• A. Unit membrane model
• B. Fluid mosaic model
• C. Reflective index model
• D. Induced fit model✓

Explanation: In 1959, Daniel E. Koshland, an American biochemist, proposed the "induced fit" model of enzyme-substrate interaction. This model is an extension of the earlier "lock and key" model proposed by Emil Fischer. The induced fit model suggests that the active site of an enzyme is flexible and can undergo conformational changes upon binding to a substrate. In other words, the enzyme is not a rigid structure with a pre-formed active site (as implied by the lock and key model), but rather, the binding of the substrate induces changes in the enzyme's structure to achieve optimal interaction.

Q72. Breathing is considered as a:

• A. Chemical process
• B. Biochemical process
• C. Mechanical process✓
• D. Both A and B

Explanation: Breathing is a mechanical process and it is a surface phenomenon.

Q73. Which of the following statements is incorrect?

• A. ∆Hn can be determined by glass calorimeter
• B. ∆Hc can be determined by bomb calorimeter
• C. ∆Hlalt of NaCl is -787 KJ mol-1
• D. Na (s) Na (g) + c ∆H -108KJmol✓

Explanation: Atomization is an endothermic process.

Q74. Competitive inhibitors and real substrate often have similar?

• A. Structure✓
• B. Chemical properties
• C. Physical properties
• D. None of these

Explanation: Because of structural similarity the competitive inhibitors may Bind to the active site but are not able to activate the catalytic sites.

Q75. Which of the following is NOT an example of evidence supporting the endosymbiotic theory?

• A. Mitochondria contain their own DNA, which is a single circular chromosome.
• B. . Mitochondria and other plastids multiply by binary fission.
• C. Mitochondria have their own ribosomes, which are 70S
• D. None of these✓

Explanation: The endosymbiotic theory posits that some eukaryotic cell organelles evolved from free-living prokaryotes. All of the mentioned options show similarity between mitochondria and bacteria, indicating that mitochondria too could have been an independent bacteria initially that got ingested by an endosymbiont cell. This is the basis of and hence supports the endosymbiont theory

Q76. To form a female zygote, the sperm cell must contribute which chromosome?

• A. X✓
• B. 2X
• C. Y
• D. XY

Explanation: In humans, if the sex chromosomes are XX then the zygote is female and if the sex chromosomes are XY then it results in a male zygote. Females can therefore also only form ovum with an X chromosome. To form a female zygote, the sperm must donate another X chromosome to the ovum to form XX zygote again.

Q77. Your neighbor has a flower garden in which there are red flowers and white Howe flowers. These flowers are diploid organisms, and flower color is an autosomal trait. The gene for red flowers (R) is dominant, while the gene for white flowers (r) is recessive. Which of the following could be the genotype of a red flower?

• A. Rr
• B. Both RR and Rr✓
• C. Only RR
• D. rr

Explanation: The trait for red flowers (R) is dominant and so is able to express itself in the homozygous (RR) and heterozygous (Rr) - condition both of which will hence yield red flowers.

Q78. How many thin filaments are arrayed around each thick filament within a sarcomere?

• A. 2
• B. 4
• C. 6✓
• D. 8

Explanation: Option A: This option is incorrect as well. The number of thin filaments surrounding each thick filament in a sarcomere is greater than four. Option B: This option is incorrect as well. The number of thin filaments surrounding each thick filament in a sarcomere is greater than four. Option C: Within a sarcomere, there are six thin filaments arranged around each thick filament. The thin filaments are composed of actin and are responsible for interacting with the thick filaments during muscle contraction. Option D: This option is incorrect. The number of thin filaments surrounding each thick filament in a sarcomere is not eight.

Q79. Centipedes belong to which class of arthropods?

• A. Arachnida
• B. Insecta
• C. Myriapoda✓
• D. Cephalopoda

Explanation: Centipedes belong to the class Myriapoda of Arthropoda. (myriapoda= many-legs)

Q80. Which of the following statements is a correct distinction between autotrophs and heterotrophs?

• A. Only heterotrophs require chemical compounds from the environment
• B. Cellular respiration is unique to heterotrophs
• C. Only heterotrophs have mitochondria
• D. Autotrophs but not heterotrophs can nourish themselves begining with nutrients that are entirely inorganic✓

Explanation: Autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are inorganic. Heterotrophs depend on autotrophs either directly or indirectly.OPTION A: Autotroph needs chemical compound from environment.OPTION B: Cellular respiration is present in both not only heterotrophy as both of them requires energy in form of ATP which is formed by cellular respiration.OPTION C: Both have mirochondria in their cells which generates energy for cells and work as power house of cell.OPTION D: Autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are inorganic.

Q81. Which of the following is a copper containing protein in electron transport chain?

• A. Plastoquinone
• B. Cytochrome - C
• C. Plastocyanin✓
• D. Ferredoxin

Explanation: It serves as an electron transfer agent between the cytochrome complex which follows Photosystem II and the entry point to Photosystem I of the non-cyclic electron transfer process. The electron transport chain is a series of electron transporters embedded in the inner mitochondrial membrane that shuttles electrons from NADH and FADH2 to molecular oxygen. In the process, protons are pumped from the mitochondrial matrix to the intermembrane space, and oxygen is reduced to form water.

Q82. In electron transport chain, ATP synthesis takes place when electrons move from:

• A. Primary Electron Acceptor (PEA) to Plastoquinone (Pq)
• B. Plastoquinone (Pq) to cytochromes
• C. Cytochrome to Plastocyanin (Pc)✓
• D. Plastocyanin (Pc) to Photosystem I (PS I)

Explanation: When an electron leaves PSII, it is transferred first to a small organic molecule (plastoquinone, Pq), then to a cytochrome complex (Cyt), and finally to a copper-containing protein called plastocyanin (Pc). As the electron moves through this electron transport chain, it goes from a higher to a lower energy level, releasing energy. Some of the energy is used to pump protons H+ from the stroma (outside of the thylakoid) into the thylakoid interior.This transfer of H+, along with the release of H+ from the splitting of water, forms a proton gradient that will be used to make ATP.

Q83. Which of these is a eucoelomate?

• A. Earthworm✓
• B. Jelly fish
• C. Sycon
• D. Planaria

Explanation: 'Eucoelomates' are those organisms having a body cavity that is a coelom — distinguished from acoelomate and pseudocoelomate. Planaria belongs to the phylum Platyhelminthes which are acoelomates (have no coelom). Sycon is a sponge that has no body arrangement at all (Phylum Porifera) Jellyfish belong to the phylum Cnidaria which is also acoelomates. Earthworms are annelids which are eucoelomates

Q84. Many sarcomeres in series make up the length of a:

• A. Microtubules
• B. Myofibril✓
• C. Myosin filament
• D. M-line

Explanation: The subunits of a 'myofibril' are sarcomeres.

Q85. If an individual does not reproduce then it's degree of fitness is?

• A. 100
• B. 50
• C. 40
• D. 0✓

Explanation: If an individual does not reproduce its degree of fitness is zero.The fittest and the best survived individual are able to reproduce.Many individuals die due to various reasons like diseases, competition, genetic factors etc. before reaching the reproductive age.

Q86. Which one is not true for H2SO4?

• A. Acid
• B. Oxidizing agent
• C. Nitrating agent✓
• D. Dehydrating agent
• E. Sulfonating agent

Explanation: H2SO4 is an acid, oxidizing agent, dehydrating agent, and sulfonating agent. It is not a nitrating agent. The nitrating agent is NO2.

Q87. Electronic configuration of M2+ ion is 2, 8, 14 and its atomic weight is 56 amu. The number of neutrons in its nucleus are:

• A. 30✓
• B. 32
• C. 42
• D. 52

Explanation: Total number of electrons in M2+ ions are 2+8+14=24, since they lost two electrons to become this ion that means neutral M will have 26 electrons. Since neutral atoms have the same numbers of electrons and protons so the number of protons in M is also 26. As the question states that the mass number of M2+ is 56. Mass number, being the sum of protons and neutrons, can be used to calculate neutrons, by subtracting protons from it(56-26=30)

Q88. Concentration of reactants and products are expressed as Moles per unit _.

• A. Area
• B. length
• C. Volume✓
• D. None of these

Explanation: The concentration of reactants and products are expressed as Moles per unit volume.

Q89. Each half reaction in ion electron method is balanced by adding:

• A. Electrons on left hand side
• B. Electron on ride hand side
• C. Both left or right hand side✓
• D. None of these

Explanation: Each reaction is balanced by adjusting coefficients and adding H2O, H+, and e− in this order: Balance elements in the equation other than O and H. Balance the oxygen atoms by adding the appropriate number of water (H2O) molecules to the opposite side of the equation.

Q90. Le-Chatelier Principle is about

• A. Reaction Mixture
• B. Reactants
• C. Equilibrium Mixture✓
• D. Products

Explanation: Le Chatelier’s Principle states that ‘for a system in equilibrium, if a change in conditions takes place, the position of equilibrium shifts to counteract that change.

Q91. Hydrolysis means reaction with

• A. Oxygen
• B. Hydrogen
• C. Water✓
• D. Air

Explanation: Hydrolysis is a reaction in which larger molecules react with water to form 2 smaller molecules and leads to the decomposition of both the molecule and water.

Q92. The decomposition of phosphorus pentachloride in the presence of moisture takes place by the following mechanism. The rate equation for this reaction will be:

• A. Rate = k [POCl3][H2O]3
• B. Rate = k [PCl5][H2O]✓
• C. Rate = k [PCl5][H2O]4
• D. Rate = [PCl5][H2O]

Explanation: For the rate equation, the reactants of ONLY the rate-determining step, which is the slow step, are taken into account in a multi-step reaction, NOT the overall equation or the fast step. Since the slow step here consists of one mole of PCL5 and one mole of H2O in the reactants, the rate equation will contain these two substances, each raised to the power 1, which is reflected in option B only.Option A takes into account the fast step only.Option C takes into account the overall reaction.Option D does not have the rate constant k mentioned in the question.

Q93. The number of reacting molecules which change their concentration in a chemical change is called:

• A. Extent of a Reaction
• B. Order of a Reaction✓
• C. Specific rate of a reaction
• D. Enthalpy of reaction

Explanation: The 'order of a chemical reaction' can be defined as the sum of the power of concentration of reactants in the rate law expression is called the order of that chemical reaction. Reactions can be a first-order reaction, second-order reaction, pseudo-first-order reaction, etc. depending on the concentration of the reactants. The order of a reaction is an experimental value. It means it is an experimentally determined parameter. It can have a fractional value as well.

Q94. Vapor pressure is measured by calculating the difference in liquid pressure and?

• A. Mercury pressure
• B. Glass pressure
• C. Atmospheric pressure✓
• D. Container pressure

Explanation: Option A) Mercury pressure and Option B) Glass pressure are incorrect because they do not have any direct relation to the measurement of vapor pressure.Option C) Vapor pressure or equilibrium vapor pressure is defined as the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases at a given temperature in a closed system. The equilibrium vapor pressure is an indication of a liquid's evaporation rate.Option D) Container pressure is also incorrect because the pressure exerted by the vapor in the container is a part of the container pressure itself. To obtain the vapor pressure, we need to subtract the atmospheric pressure from the total pressure exerted by the mixture of vapor and air in the container.

Q95. 273 mL of a gas at STP was taken to 27oC and 600 mm pressure. The final volume of the gas would be:

• A. 273 mL
• B. 300 mL
• C. 380 mL✓
• D. 586 mL

Explanation: The correct answer is '380 mL'. You can use the following image as the solution. As it is a numerical it can have one answer.

Q96. Which of the following has six isotopes?

• A. Manganese
• B. Tin
• C. Calcium✓
• D. Carbon

Explanation: Calcium has six stable isotopes: 40, 42, 43, 44, 46, 48 Manganese has four stable isotopes: 52, 53, 54, 55 Tin has ten isotopes: 112, 114, 115, 116, 117, 118, 119, 120, 122, 124 Carbon has three isotopes: 12, 13, 14. So option C is correct.

Q97. How many molecules are there in 2.1 moles of CO₂:

• A. 3.49 x 10⁻²⁴
• B. 2.53 x 10²⁴
• C. 1.26 x 10²⁴✓
• D. 3.79 x 10²⁴

Explanation: Since there are 2.1 moles of CO₂, we can easily find out the number of molecules present in it by multiplying 2.1 with the Avagadro's constant, which is 6.02 × 10²³. Hence, the answer would be approximately 1.2 x 10²⁴. The answer choice that is closest to the obtained value is 1.26 x 10²⁴. Please do not calculate the total number of atoms in this question; you have only been asked to calculate the total number of molecules.

Q98. Avogadro's constant is the number of:

• A. Electrons present in 2g of H
• B. Atoms in 24g of Mg✓
• C. Atoms in 1g of He
• D. Molecules in 35.5g of Chlorine

Explanation: Avogadro's Number (NA) is the number of atoms, molecules, ions or anything in one mole of the respective substance. As 6.02 x 1023 atoms, molecules, ions or electrons are present in one mole; therefore, this number is known as Avogadro's number. Only 24g of Mg equals one mole of Mg. Thus, only 24g of Mg has Avogadro's number of atoms. 1g of He equals 1/2 mole of He. Thus it has half the number of atoms than Avogadro's number. 35.5g of chlorine equals 1/2 mole of chlorine gas. Thus, it has half the number of molecules than Avogadro's number. 2g of H equals two moles. Each mole of H atoms has 1 mole of electrons only, so two moles of H have twice the number of electrons than Avogadro's number.

Q99. Which of the following fertilizers has the maximum percentage of nitrogen in solid state at 46% N?

• A. Ammonia
• B. Urea✓
• C. Di ammonium hydrogen phosphate
• D. Ammonium nitrate

Explanation: Explanation is given below:

Q100. How many electrons can occupy in 7th energy level of an atom. Calculate by using 2n2 formula

• A. 24
• B. 5
• C. 72
• D. 98✓

Explanation: The formulae/expression 2n2 can be/was derived from the number of orbitals present in each of the main energy levels. Formula=2n2 = 2(7)2 = 2(49) = 98

Q101. In the discharge tube positive rays move in which direction?

• A. Towards anode
• B. Towards cathode✓
• C. Move randomly
• D. Move towards vacuum in the tube

Explanation: In discharge tube cathode rays (a beam of negative particles) and canal rays (positive rays) moves opposite to each other. They will experience a magnetic force in the same direction, if a normal magnetic field is switched on.Positive charges move towards cathode whereas negative charges move towards the anode.

Q102. Which of the following statements is incorrect about amorphous solids?

• A. They are isotropic
• B. They are rigid and incompressible✓
• C. They melt over a wide range of temperatures.
• D. There is no orderly arrangement of particles

Explanation: In amorphous solids, the arrangement of particles is irregular in all directions; hence, the value of any physical property is the same in any direction. Hence, they are isotropic. Therefore, Option B is the answer.

Q103. Salt Bridge is used for the purpose of:

• A. Producing Electrons
• B. Circuit Completion✓
• C. Increasing speed of electrons
• D. All of these

Explanation: You need a salt bridge to complete the circuit as it contains mobile ions that act as charge carriers. It allows current to flow while allowing different electrolytes to be in contact with the anode and cathode. Thus, option B is correct.

Q104. In one second if the concentration changes from 0.1 to 0.25 then the rate will be:

• A. 0.02 moles/dm3s-1
• B. 0.03 moles/dm3s-1
• C. 0.15 moles/dm3s-1✓
• D. 0.11 moles/dm3s-1

Explanation: Rate of reaction = change in concentration/time = 0.15mol dm-3/1s = 0.15 mol dm-3 s-1

Q105. The equation shows the reaction between element X and dilute hydrochloric acid. X(s) + 2HCl(aq) -> XCl2(aq) + H2(g) What types of bonding is present in element X and in compound XCl2?

• A. Option A
• B. Option B
• C. Option C
• D. Option D✓

Explanation: Elements, in this case, X, can not possess a covalent bond alone so it should be a metallic bond, this rules out options A and B. Since now it is established that X is metal and chlorine is non-metal, now the type of bonding possessed between a metal ion and a non-metal ion is ionic so that rules out option C while we are left with correct option D.

Q106. The common features, among the species CN-, CO, and NO+ are:

• A. Bond order 3 and Isoelectronic✓
• B. Bond order three and weak field ligands
• C. Bond order two and π acceptors
• D. Isoelectronic and weak field ligands

Explanation: Each of these have same number of electrons; Number of electrons in CO = 6+8 = 14 Number of electrons in CN- = 6+7+1 = 14 Number of electrons in NO+ = 7+8-1 = 14 The species having same number of electrons are called iso-electronic. Iso-electronic species have same bond order. Bond order is number of chemical bonds present between a pair of atoms. There are 3 chemical bonds between C and O in CO, C and N in CN- and N and O in NO+ so all of these have same bond order of 3. Hence, all the given species are iso- electronic and have same bond order. So, option A is correct. CO and CN- are strong field ligands, while NO+ is weak field ligand. Weak field ligands are ones that produce small splittings between the d orbitals and form high spin complexes. Hence option B and D are incorrect. Weak field ligands are all π - donors. Strong field ligands are all π - acceptors. Hence option C is also incorrect.

Q107. Chlorine is manufactured commercially by the electrolysis of aqueous sodium chloride (brine). Which other products are made in this process?

• A. Hydrochloric acid and hydrogen
• B. Hydrogen and sodium
• C. Hydrogen and sodium hydroxide✓
• D. Sodium and sodium hydroxide
• E. Hydrochloric acid and sodium

Explanation: Gas extraction: Chlorine can be manufactured by the electrolysis of a sodium chloride solution (brine), whichis known as the Chlor Alkali process. The production of chlorine results in the co-products of caustic soda (sodium hydroxide, NaOH) and hydrogen gas (H2).

Q108. Which of the following molecules have zero Dipole moments?

• A. CCl4
• B. CO2
• C. Cl2
• D. C6H6
• E. All of the above✓

Explanation: Dipole moments occur when there is a separation of charge. They can occur between two ions in an ionic bond or between atoms in a covalent bond; dipole moments arise from differences in electronegativity. The larger the difference in electronegativity, the larger the dipole moment. The distance between the charge separation is also a deciding factor in the size of the dipole moment. The dipole moment is a measure of the polarity of the molecule.

Q109. Which of the following is the correct equation to calculate relative molecular mass of a gas.

• A. M = mPR / VT
• B. M = PV / mRT
• C. M = mPRT / V
• D. M = mRT / PV✓

Explanation: Since PV=NRT where n = m / M PV=MRT / M M=mRT / PV.

Q110. Which of the following reagents will reduce butanoic acid to butanol?

• A. LiAlH4✓
• B. LiAlH4.H2O
• C. Mg(BH4)2
• D. All of the above

Explanation: Carboxylic acids can be converted to primary alcohols using LiAlH4 since NaBH4 or other reducing agengts are not strong enough to convert carboxylic acids or esters to alcohols. An aldehyde is produced as an intermediate during this reaction, but it cannot be isolated because it is more reactive than the original carboxylic acid. For example, butanoic acid can be reduced to butanol when reacted with lithium aluminum hydride as shown below.

Q111. An ester is prepared by the reaction of:

• A. Two alcohols
• B. Carboxylic acid and alcohol✓
• C. Ketone and alcohol
• D. Aldehyde and alcohol
• E. All of these

Explanation: When a carboxylic acid is treated with an alcohol and an acid catalyst, an ester is formed (along with water):

Q112. Hydrolysis of acyl chloride results in the formation of:

• A. Acid anhydride
• B. Carboxylic acid✓
• C. Amides
• D. Esters

Explanation: Aqueous acid chloride is a very acidic solution due to formation of a mixture of strong acid and a weak acid. This hydrolysis reaction is an elimination reaction and water is participated as a reagent. This reaction completely converts acid chloride to a carboxylic acid and HCl (Hydrochloric acid).

Q113. Carbon dioxide is an Example of?

• A. Ionic Solid
• B. Metallic Solid
• C. Molecular Solid✓
• D. Covalent Solid

Explanation: A molecular solid is composed of molecules held together by van der Waals forces. It is a solid that consists of discrete molecules. All these properties are of CO2 so it is an example of molecular solid as it has relatively Van Der Waals London Dispersion Forces. Hence, option C is correct.

Q114. Treatment of propionaldehyde with Dil. the NaOH solution gives:

• A. CH3 CH2COOCH2C2H5
• B. CH3 CH2 CHOH CH2 CH2 CHO
• C. CH3 CH2 CH (OH) CH(CH3) CHO✓
• D. CH3 CH2 COCH2 CH2 CHO

Explanation: All the other options are incorrect.

Q115. Which of the following will react with water?

• A. CHCl3
• B. Cl3CCHO✓
• C. CCl4
• D. ClCH2CH2Cl

Explanation: Cl3CCHO will react with water. Water is a polar solvent. Like dissolves like. A polar solvent will be dissolved in a polar and a non-polar compound will be dissolved in a nonpolar solvent. CCl4, ClCH2CH2Cl are non-polar. So they will not be able to dissolve in water. Cl3CCOOH will form hydrogen bonds with water due to which it will dissolve in water. Such hydrogen bonding is not present in the case of CHCl3. Chloral (Cl3CCHO) reacts with water to form chloral hydrate, CCl3CH(OH)2

Q116. In the reaction of p- chlorotoluene with KNH2 in liquid NH3, the major product is:

• A. O - toluidine
• B. M - toluidine✓
• C. P- toluidine
• D. P-chloroaniline

Explanation: We know that the reaction of p-chlorotoluene with KNH2 in liquid NH3 proceeds via the benzyne mechanism. The primary stage in the mechanism is a base-promoted Dehydrohalogenation of chlorobenzene and the intermediate formed in the step will contain a triple bond in an aromatic ring called benzyne.Complete step by step answer:We know that para-Chlorotoluene initially forms benzyne with methyl as a substituent. When -NH2 attacks at carbon which is bearing triple bond it gives a mixture of Meta and para-toluidine. The major product formed is m-toluidine because of the formation of carbanion at the meta position by the attack of nucleophiles and it is more stable compared to the para position. Hence option B is correct.The mechanism by which the reaction takes place,First step: Removal of a proton by KNH2 from the Meta position of p-chlorotoluene which provides benzyne as an intermediate.Second step: Since benzyne is susceptible to nucleophilic attack and hence the nucleophile present within the solution is NH2 which may attack each side of the Benzene bond. Meta product is major as just in case of an attack on 1 the negative charge formed is going to be farthest from the methyl group which facilitates less +1 and hence more stable negative ions.We can write the chemical equation for this mechanism as,So, the correct answer is Option B.Note:Two mechanisms were proposed for the nucleophilic aromatic substitution, one among the mechanisms involves a benzyne because the intermediate form is a benzyne and so, it is named as benzyne mechanism. Arynes or benzyne are extremely reactive groups resulting from an aromatic ring by the elimination of two substituents.

Q117. The order of reactivities of the following alkyl halides for an SN2 reaction is:

• A. RF > RCl > RBr > RI
• B. RF > RBR > RCl > RI
• C. RCl > RBr > RF > RI
• D. RI > RBr > RCl > RF✓

Explanation: The reactivity of the alkyl halide in SN2 reaction is decided by the ease with which the halide leaves the substrate. Larger the size of the halide ion, more is the leaving ability.As per the leaving ability, the order is I−>Br−>Cl−>F-. Hence reactivity order is RI > RBr > RCl > RF due to higher stability of I- ion (due to its higher size). Hence, I ion is easily displaced by nucleophile

Q118. - ROR is the nucleophile of

• A. Alcohols
• B. Esters
• C. Cyanides
• D. Ethers✓
• E. Aldehydes

Explanation: We have to look at the general form of given functional groups.

Q119. RMgX is an organometallic compound, generally known as:

• A. Grignard's Reagent✓
• B. Baeyer's Reagent
• C. Ether
• D. Ester
• E. Aldehyde

Explanation: A Grignard reagent of the Grignard compound is a chemical compound with the generic formula R−Mg−X, where X is a halogen and R is an organic group, normally an alkyl or aryl.

Q120. Which of the following has the maximum number of unpaired d electrons?

• A. Mg 2+
• B. Ti 3+
• C. V 3+
• D. Fe 2+✓

Explanation: The electron configuration for Fe2+ will be 1s2 2s2 2p6 3s2 3p6 4s2 3d4 because it has lost two electrons.All four electrons in d-orbital are unpaired.The Magnesium ion electron configuration will be 1s22s22p6.For the V3+, called the Vanadium ion, we remove one electron from 3d3 and two from the 3d2 leaving us with: 1s2 2s2 2p6 3s2 3p6 3d2.Electronic configuration of Ti3+ is [Ar] 3d1,which means it only has 1 unpaired electron.

Q121. For which mechanism the first step involved is the same?

• A. E1 and E2
• B. SN1 and E2
• C. E1 and SN2
• D. E1 and SN1✓

Explanation: In the first step, the bond between the carbon atom and the leaving group breaks to produce a carbocation and, most commonly, an anionic leaving group. This is the same in SN1 and E1 reactions.

Q122. How many chain isomers can be obtained from the alkane C6H14?

• A. 7
• B. 6
• C. 5✓
• D. 4

Explanation: 2(nc-4) + 1, nc is no. of carbon atoms this formula is valid for alkanes till heptane There are five chain isomers possible for hexane molecule as shown below:

Q123. IUPAC name of C6H5 - CH2 - CH2 - NH2 is:

• A. 2-phenyl ethanamine✓
• B. 2-phenyl ethanamide
• C. 2-phenyl ethenamine
• D. 3-phenyl ethanamine

Explanation: The compound C6H5−CH2−CH2−NH2 is an amine. The parent hydrocarbon is ethane. The substituent (phenyl group) is present at a second carbon atom. Hence, the IUPAC name is 2-phenyl ethanamine

Q124. In 3rd series of transition elements, paramagnetic behaviour is maximum for Mn +2 and :

• A. Cr3+✓
• B. Ti3+
• C. V3+
• D. Zn2+

Explanation: Electronic configuration of chromium 3+ is [Ar] 3d3. Cr3+ has 3 unpaired electrons in its outer most shell and thus it’s the element which shows the most paramagnetic behaviour out of the other options given. A paramagnetic electron is an unpaired electron. An atom is considered paramagnetic if even one orbital has a net spin.The unpaired electrons of paramagnetic atoms realign in response to external magnetic fields and are therefore attracted.

Q125. Electronic configuration of chromium (Proton number 24) is:

• A. [Ar] 3d4 4s2
• B. [Ar] 3d2 4s2
• C. [Ar] 3d5 4s1✓
• D. [Ar] 3d5 4s2

Explanation: Chromium(Cr) and Copper(Cu) are two special cases in which electron from 4s orbital jumps to 3d so 4s orbital has only a single electron in it.In options there is only one option that has a single electron in 4s orbital which is C. A is a wrong form to write Cr electronic configuration because technically when 3d has 4 electrons a single electron will jump from 4s to 3d to make it 5 in 3d, as it is a more stable state. B and D cannot be right because they correspond to electronic configuration of atoms having a proton number 25.

Q126. Benzene can be prepared from:

• A. From Petroleum
• B. From Coal
• C. From Acetylene
• D. From Phenol
• E. All of these✓

Explanation: This is the following explanation:

Q127. The electrophilic reactions of Benzene are:

• A. Halogenation
• B. Nitration
• C. Sulphonation
• D. Alkylation and Acylation
• E. All of these✓

Explanation: The electrophilic substitution of benzene is the one where an electrophile substitutes the hydrogen atom of benzene. Basic examples of electrophilic substitution reaction of benzene are nitration, sulfonation, halogenation, Friedel Crafts alkylation, and acylation, etc.

Q128. CH ≡ CH + 2AgNO3 -> AgC ≡ CAg + 2HNO3 represents _ property of acetylene.

• A. Basic
• B. Acidic✓
• C. Dehydrating
• D. Physical
• E. None of the above

Explanation: Acetylene is a known weak acid as it can be seen when dissolved in silver nitrate it can give off its two hydrogen ions - thus acting as a acid.

Q129. The diagram below represents the process of:

• A. Hydrolysis
• B. Condensation✓
• C. Neutralization
• D. Metabolism

Explanation: When two monomers join together to form a single product, with the removal of H2O, the process is called the condensation process. Hence, option B is correct.

Q130. Dehydration of ethanol at 100 oC in the presence of concentrated H2SO4 gives:

• A. Ethene✓
• B. Ethane
• C. Ethyne
• D. Ether

Explanation: Dehydration reactions involve the removal of a water molecule from a compound. This process is commonly used to prepare alkenes from alcohols. However, dehydration reactions are not suitable for preparing alkanes, ethyne (acetylene). Overall, the suitability of dehydration reactions depends on the presence of appropriate functional groups within a molecule. Alkenes, which contain a carbon-carbon double bond, are suitable for dehydration as the removal of a water molecule can occur from the hydroxyl group (-OH) of an alcohol. Alkanes, ethyne, and ethers lack the necessary functional groups and do not undergo dehydration reactions under normal conditions.

Q131. Phenol reacts with CH3COCl to give:

• A. Acid
• B. Ester✓
• C. Alcohol
• D. Aldehyde

Explanation: When phenol reacts with acyl chloride, a condensation reaction occurs with the removal of OH group from phenol and Cl atom from acyl chloride. The result is the formation of an ester. Phenols differ from alcohol in the respect that they do not react with carboxylic acids directly but instead have a reaction with the faster alternative, acyl halides to form esters. The reaction can be illustrated below: 276016_284166_ans.png (1847×385) (haygot.s3.amazonaws.com

Q132. Benzene also undergoes electrophilic substitution with fuming sulphuric acid for several hours. The electrophile in this reaction is:

• A. SO2
• B. SO3✓
• C. SO4
• D. H2SO4

Explanation: When benzene undergoes electrophilic substitution with fuming sulphuric acid (H2SO4), the electrophile involved in the reaction is SO3, which is derived from the sulphuric acid. So, option B is the appropriate answer.

Q133. Which one is not a nucleophile?

• A. C3H7O-
• B. SCN-
• C. H2C+✓
• D. NH3

Explanation: H2C+ is a carbocation, which is an electron-deficient species i.e. an electrophile. It is missing a pair of electrons and cannot donate a pair of electrons to act as a nucleophile.

Q134. A solution which does not tend to vary in pH is called?

• A. Acidic solution
• B. Buffer solution✓
• C. Bases solution
• D. Super saturated solution

Explanation: A solution that does not tend to vary in pH is called a buffer solution. Therefore, option B is correct.

Q135. Phenol is more reactive than benzene towards electrophilic substitution. This characteristic is due to which of the following?

• A. Hydrogen bonding
• B. Inductive effect
• C. Strong mesomeric effect✓
• D. Weak mesomeric effect

Explanation: The presence of the hydroxyl group in phenol allows for extensive resonance delocalization of electrons in the benzene ring, resulting in a strong mesomeric effect. This mesomeric effect stabilizes the positive charge on the intermediate during electrophilic substitution, making phenol more reactive. Hence, option C is correct.

Q136. The outer shell configuration of transition block elements is given by:

• A. (n-1) d1-10 na2
• B. (n-1)d1-10(n-1)s0-2
• C. (n-1)d1-10ns0-2✓
• D. nd1-10ns0-2

Explanation: The formula for calculating the required electronic configuration is (n-1)d1-10, ns1-2. Hence, only option C is correct.

Q137. If the body is rotating with uniform angular velocity, then its torque is:

• A. Zero✓
• B. 90
• C. 1
• D. -1

Explanation: A body moving with uniform angular velocity is having zero Angular acceleration so since torque = force * moment arm (where F=ma and a here is zero as object s not accelerating. ) so F=0 So T=0Torque is the moment of force about a body. T = F . rAngular velocity = w = d z /dt Linear velocity = v = rwlinear acceleration=a = r .[ d w/ dt ]F = ma = mr [ dw/dt]T = F.r = mr^2 [dw/dt] , mr^2 = I , the moment of inertiaT = I . [dw/dt]Now if w = angular velocity is a constant , then dw/dt = 0So that T = I[0] =0

Q138. The angular velocity of the minute hand of a clock is

• A. 2π/60rads-1
• B. π/24rads-1
• C. 2π/3600rads-1✓
• D. π/3600rads-1

Explanation: Explanation is given below:

Q139. When a body is whirled in a horizontal circle by means of a string the centripetal force is supplied by

• A. Mass of a body
• B. Velocity of body
• C. The tension in the string✓
• D. Centripetal acceleration

Explanation: Tension is the only force that provides the centripetal force in this case.

Q140. Power developed by a person on eating 100g of ice per minute is (Latent heat of ice is 80 cal/g):

• A. 130 W
• B. 560 cal/sec
• C. 560 J/sec✓
• D. none of these

Explanation: A mass of ice eaten by the man per second. m =100/60=5/3 g/s Latent heat of ice, L = 80 cal/g. Therefore, energy required per second by the man in eating the ice, i.e., power developed by the man. = mL =5/3 x 80 cal/s 3 =5x80/3x4.2J/s=560W

Q141. A block hangs freely from the end of a spring. A boy then slowly pushes the block upwards so that the spring becomes strain free. The gain in gravitational potential energy of the block during this process is equal to:

• A. work done by the boy against the gravitational force acting on the block
• B. loss of energy stored in the spring minus the work done by the tension in the spring
• C. work done on the block by the boy plus the loss of energy stored in the spring✓
• D. work done on the block by the boy minus the work done by the tension in the spring

Explanation: Let xo be the initial extension of the spring. Then the initial energy stored in the spring is: ½kxo2 The gain in gravitational potential energy: mgh = mgxo The work done increases the gravitational potential energy and decreases the spring’s potential energy. The total energy gained = gain in the gravitational potential energy - loss in spring’s potential energy. Therefore, work done by the boy (wb) = gain in the gravitational potential energy - loss in spring’s potential From here you can see that the gain in the gravitational potential energy of the block = work done by the boy + loss in the spring’s potential energy. Therefore, option C is the correct one.

Q142. The oscillating object overshoots the rest position due to:

• A. Restoring force
• B. Inertia✓
• C. Gravitational potential energy
• D. Elastic potential energy

Explanation: To get oscillations, a body is pulled away from its resting or equilibrium position and then released. The body oscillates due to a restoring force. Under the action of this restoring force, the body accelerates and overshoots the rest position due to inertia.

Q143. The angular measurement is known as _ measurement

• A. parameter
• B. area
• C. circumference✓
• D. all of these

Explanation: As θ= Angular displacement or measurement Explanation for this question will be added soon.As θ= Angular displacement or measurement S= arc length or circumference r= radius of circle Since θ= S/r Hence angular displacement is related to circumference or arc length as rhey are directly related.

Q144. If we are standing in a bus and the driver applies a brake then we feel:

• A. A pseudo force pushes backwards
• B. A pseudo force pushes forwards✓
• C. A real force pushes backwards
• D. A real force pushes forwards

Explanation: A pseudo force (also called a fictitious force, inertial force, or d’Alembert force) is an apparent force that acts on all masses whose motion is described using a non-inertial frame of reference, such as a rotating reference frame. Pseudo force comes into effect when the frame of reference has started acceleration compared to a non-accelerating frame.

Q145. Acceleration in the simple pendulum is always _ to displacement.

• A. Inversely proportional
• B. Directly proportional
• C. Acting positive✓
• D. Independent

Explanation: In terms of directly proportional and sign, the acceleration in a simple pendulum is directly proportional to the displacement but has opposite signs. When a simple pendulum is displaced from its equilibrium position, the acceleration is directly proportional to the displacement. This means that as the displacement of the pendulum bob increases, the magnitude of the acceleration also increases proportionally. However, the sign of the acceleration is opposite to the displacement. When the pendulum bob is displaced to one side, the acceleration acts in the opposite direction, towards the center of the oscillation. As the pendulum bob swings back and forth, the acceleration continuously changes its direction, always directed towards the center of the oscillation and opposite to the displacement. For example, if the pendulum bob is displaced to the right, the acceleration will be directed towards the left. If the pendulum bob is displaced to the left, the acceleration will be directed towards the right. So, in summary, the acceleration in a simple pendulum is directly proportional to the displacement but has an opposite sign.

Q146. The slope of displacement-time graph has the unit:

• A. m
• B. s
• C. m/s²
• D. m/s✓

Explanation: The slope of a displacement-time graph is given by:Δy/Δx = Δs/Δt, which is equal to velocity. Hence, the correct answer is m/s.Provided below, is an example where Δs, i.e. change in displacement, is given as 17.5 m, and Δt, i.e. change in time, is given as 5 seconds. The above formula is applied to find velocity, by finding the value of the slope.

Q147. On a planet, a vertically-launched projectile takes 12.5 s to return to its starting position. The projectile gains a maximum height of 170 m. The planet does not have an atmosphere. What is the acceleration of free fall on this planet?

• A. 2.2 m s−2
• B. 8.7 m s−2✓
• C. 27 m s−2
• D. 54 m s−2

Explanation: Explanation is given below:

Q148. If a wave can be polarized, it means, it is:

• A. Longitudinal wave
• B. Stationary wave
• C. Superimposed wave
• D. Transverse wave✓

Explanation: Only transverse waves can be polarised. Longitudinal waves cannot be polarised. Transverse: vibrations perpendicular to the direction of travel of the wave. Longitudinal: vibrations parallel to the direction of travel of the wave. Sound waves are longitudinal so they cannot be polarised. Polarised: the wave vibrations occur in one plane only Unpolarised: the wave vibrations occur in all planes perpendicular to the direction of travel. The reason that only transverse waves can be polarised is that their vibrations can potentially occur in all directions perpendicular to the direction of travel. It is therefore possible to confine the vibrations to a single plane. Or put another way an unpolarised transverse wave is a 3D shape, it is therefore possible to confine it to a 2D shape (a plane). The vibrations of a longitudinal wave occur along a single line, it is therefore not possible to confine that to a plane, i.e. a 1D shape cannot be confined within a 2D shape. Similarly, Stationary waves and superimposed waves can not be polarised as they are along a single line. VIDEO EXPLANATION

Q149. The body of a car is supported by four springs each of constant 2000 Nm-1. What will be the value of spring constant for this combination of springs?

• A. 2000 Nm-1
• B. 600 Nm-1
• C. 8000 Nm-1✓
• D. 4000 Nm-1

Explanation: The effective spring constant of multiple springs acting in parallel is equal to the sum of each individual spring constant. Because all spings in parallel must deform equally, the force required to deform the parallel springs will be equal to the sum of forces to deform each individual spring by the same amount.

Q150. The diagram shows a wire, carrying an electronic current I, placed between the poles of a magnet. In which direction does the force on the wire act?

• A. Into the paper✓
• B. Towards the N pole of the magnet
• C. Out of the paper
• D. Towards the S pole of the magnet

Explanation: F=I(LxB) The direction of L is in the direction of the current. The direction of the magnetic force F is the right angle to the plane containing L and B. It is given by right-hand rule of the cross product (into the paper).

Q151. The ratio of the number of turns in primary and secondary coils of a transformer is 1:20. The ratio of the currents in the primary and secondary will be

• A. 1:20
• B. 20:1✓
• C. 1:400
• D. 400:1

Explanation: Explanation is giving below:

Q152. The change in resistance of metallic conductor at temperature below 0 degrees is:

• A. Non-linear
• B. Curve
• C. Linear✓
• D. Curvilinear

Explanation: The resistance increases as the temperature of the metallic conductor increases. The graph between resistance and temperature is linear for both increasing and decreasing temperatures.

Q153. When an ideal gas of constant mass is heated in a container of fixed volume, what is the reason for the increase in pressure of the gas?

• A. The number of molecules per unit volume increases
• B. The molecules occupy greater volume of the container
• C. The average force per impact at the container wall increases✓
• D. The molecules collide with each other with greater force

Explanation: The number of molecules per unit volume cannot increase because as specified by the question statement, the mass is constant. Moreover, molecules can only occupy the volume of the container. Since the volume of the container is fixed, they can't occupy a greater volume. Molecules do collide with each other with greater force but that is not the reason for the increase in the pressure of the gas. Molecules of gases are contiually colliding with each other and with the walls of the container. When a molecule collides with the wall, it exerts a small force on the wall. The pressure exerted by the gas is due to the sum of all these collision forces with the wall. As heat is supplied, molecules gain greater Kinetic Energy and collide with the wall harder and faster.

Q154. Some ice, at its melting point, is added to m kg of water at the initial temperature of 290K. The ice melts completely and the final temperature of the water is 273K. If c is the specific heat capacity of the water and L is the latent heat of fusion of ice, what is the minimum mass of ice that is required?

• A. 17mc/L✓
• B. L/17mc
• C. 17m/Lc
• D. 290m/Lc

Explanation: Refer to the working below:

Q155. Which one of the following is not electromagnetic in nature.

• A. X-rays
• B. Gamma rays
• C. Cathode rays✓
• D. Infrared rays

Explanation: Cathode ray is made up of electrons, so it is not an electromagnetic wave. They are deflected neither by the electric field nor by the magnetic field.

Q156. The force between two charges Q and q, separated by a distance is F. What will be the force between them when the distance between them is d/2?

• A. 4 F✓
• B. 2 F
• C. F
• D. F/2

Explanation: According to Coulomb's law of electrostatic force, the force between the two charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. F = k q1q2/d² Where k is constant, q1 and q2 are two point charges and d the distance between them. If the distance between the charges is d/2 and there is no change in charges The new force becomes F’=kq1q2/(d/2)² F’=k q1q2/(d²/4) F’=4F Which means, force will be 4 times of the initial value.

Q157. What is the relationship between power, urrent and voltage?

• A. P=V/I
• B. P=VI✓
• C. 2P=l+V
• D. All of them

Explanation: is correct as it tells us about the actual relationship between power , current and voltage . Electric power is the rate at which work is done or energy is transformed into an electrical circuit. P=W/t P= QV/t *I = Q/t P= IV

Q158. Object A has a charge of 15 mC, and object B has a charge of 10 mC. Which statement is true about the electric forces on the objects?

• A. FAB = -3 FBA
• B. FAB = - FBA✓
• C. 3 FAB = - FBA
• D. -3 FAB = 2 FBA

Explanation: .

Q159. Magnetic force on a charged particle is:

• A. QvBl
• B. None of these
• C. QvB cosθ
• D. QvB sinθ✓

Explanation: When a charge moves through a magnetic field, a force is applied on it which is given by:F = QvB sinθQvBl is the motional EMF produced when a conductor moves through a static magnetic field.

Q160. Velocity of sound in air is 332m/s. Velocity of sound in vacuum would be:

• A. More than 332m/s
• B. Less than 332m/s
• C. 332m/s
• D. Zero✓

Explanation: Sound waves are longitudinal waves and they need a medium to travel. Thus, they cannot travel in vaccum.

Q161. In a full-wave bridge rectification, the number of diodes used are:

• A. 1
• B. 2
• C. 3
• D. 4✓

Explanation: The full-wave rectifier circuit consists of 4 diodes arranged in a tetrahedral connection. When we have the upper side of the AC supply as positive, the current flows through D1 to the load and returns through D2 at the temporary negative terminal of the AC supply. When the bottom side of the AC supply is positive, due to the constant change in polarity, the current, conventionally, flows through D3 to the load and returns to the supply by passing through D4. It reaches the supply at the now negative terminal of the AC supply which is the upper side of the supply.

Q162. An alternation voltage V (in volts) is represented by the equation:V = 300 sin (100πt) What is the value of “f” for this voltage?

• A. 100 Hz
• B. 50 Hz✓
• C. 25 H
• D. 200 Hz

Explanation: Voltage = Maximum Voltage x sin (2πft)Therefore, 2f = 100 and frequency = 50 Hz

Q163. The use of a capacitor filter in a rectifier circuit gives satisfactory performance only when the load:

• A. The current is high
• B. The current is low✓
• C. Voltage is high
• D. The voltage is low

Explanation: A capacitor filter in a rectifier circuit is used to smooth out the output voltage and reduce the ripple factor.Only when load resistance is large, discharge time is large, and the current passing through it is low

Q164. The waves which can travel directly along surface of the earth are known as

• A. ground waves✓
• B. X-ray
• C. α − rays
• D. sky waves

Explanation: The waves which can travel directly along surface of the earth are known as ground waves. The ground wave is the preferred propagation type for long distance communication using frequencies below 3 MHz (the earth behaves as a conductor for all frequencies below 5 MHz). The ground wave is also used for short distance communications using frequencies between 3 and 30 MHz.

Q165. A TV tower has a height of 100m. The average population density around the tower is 1000 per km2 . The radius of the earth is 6.4x106 m. × The population covered by the tower is

• A. 2x106
• B. 3x106
• C. 4x106✓
• D. 6x106

Explanation: This is the following solution:

Q166. The valence band and conduction band of a solid overlap at low temperature, the solid may be:

• A. a metal✓
• B. a semiconductor
• C. an insulator
• D. none of these

Explanation: According to band theory of solids, in the valence band and the conduction band overlap in conductors.

Q167. Assertion: In n-type semiconductor electrons are the majority charge carriers and holes are minority charge carriers.Reason: n-type semiconductor is electrically neutral.

• A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion.
• B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion.✓
• C. If Assertion is true statement but Reason is false.
• D. If both Assertion and Reason are false statements.

Explanation: In n-type semiconductor electrons are the majority charge carriers and holes are minority charge carriers and n-type semiconductor is electrically neutral.

Q168. Platinum wire becomes yellow at a temperature of _ degree C.

• A. 900
• B. 500
• C. 1300✓
• D. 1600

Explanation: If black wire of platinum is heated its colour first appears red, then yellow and finally white. This can be explained by wein’s displacement law. At low temperatures (500 degree celsius) the wire emits electromagnetic radiations of longer wavelengths so it appears dull red. As the temperature increases the wavelength emitted shortens and the colour changes from red to orange (1100 degree celsius) to yellow (1300 degree celsius) and ultimately white(1600 degree celsius) when radiations of all wavelengths are being emitted. PMC PAPER 23 2021 150-210

Q169. The electron is purely a _ when free.

• A. Particle nature
• B. Wave nature
• C. Dual nature✓
• D. It transforms to photon

Explanation: the electron is purely a dual nature when it's free. In quantum mechanics, electrons can behave as both particles and waves, depending on how they are observed or measured. This duality is known as wave-particle duality and is a fundamental aspect of quantum mechanics. When electrons are free, meaning they are not bound within an atom or molecule, their wave-like properties become more apparent.

Q170. Work function was given by:

• A. Newton
• B. Heisenberg
• C. Einstein✓
• D. Bohr

Explanation: Work function is the minimum energy required to cause the photoelectric effect. It is constant for a particular material. Absorption of energy equal to the work function causes electrons to be excited enough to come up to the surface of the material. Surplus energy will cause the emission of the electron from the surface. This can be explained from the Photoelectric Effect equation discovered by Einstein: KEmax = hfo + hf (where KEmax is the energy of the incident photon, hfo is the work function, hf is the KE of the electron)

Q171. In Davisson-Germer experiment, the diffracted electron beam from crystal shows

• A. Particle property
• B. Light property
• C. Wave property✓
• D. Quantum property

Explanation: Diffracted electron beam from crystal shows wave nature. Davisson Germer experiment showed that electron beams can undergo diffraction when passed through atomic crystals. This shows the wave nature of electrons as waves can exhibit interference and diffraction.

Q172. If the decay or disintegration constant of a radioactive substance is λ, then its half-life and mean life are respectively

• A. Option A
• B. Option B✓
• C. Option C
• D. Option D

Explanation: The explanation for this question will be added soon!

Q173. What is the number of spectral series in the hydrogen spectrum?

• A. Four
• B. Three
• C. Five✓
• D. One

Explanation: The five spectral series are Lyman, Balmer, Paschen, Brackett and Pfund. In the Lyman series, the electron falls back to n = 1. The spectral lines obtained are in the UV region of the electromagnetic spectrum. In the Balmer series, the electron falls back to n = 2 and the spectral lines obtained are in the visible region of the EM spectrum. Paschen, Brackett, and Pfund spectral lines are obtained in the Infrared region of the EM spectrum.

Q174. In the SI system of units, the centripetal force is measured in?

• A. J
• B. N✓
• C. T
• D. W

Explanation: Joules is used to measure work.Centripetal force is measured in newtonsand is calculated as mass multiplied by tangential velocity squared, divided by the radius.The SI unit of torque is newton per metre. Torque is the measure of force that can cause an object to rotate about an axis.Watt is the measurement of work per second and is used for electricity.Therefore, option B is correct.

Q175. If two equal masses are in motion with same individual speeds, we can conclude that:

• A. Their momentums are same✓
• B. Their momentums can be different from each other
• C. Their kinetic energies are different from each other
• D. Their total energies are same

Explanation: Two equal masses moving with same individual speeds, we can conclude that their momentum are same. So the correct option is A.

Q176. Which type of energy does the capacitor store?

• A. Kinetic
• B. Potential✓
• C. Thermal
• D. Light

Explanation: A capacitor stores electrical potential energy. When a capacitor is charged, electrical potential energy is stored in the electric field between its plates. The amount of energy stored in a capacitor depends on its capacitance and the voltage across it.

Q177. Speed of sound is fast in moist air because:

• A. Moist air is heavier than dry air
• B. Value of gamma is more for moist air
• C. Density of moist air is less than density of dry air✓
• D. Density of moist air is more than density of dry air

Explanation: The speed of sound in dry air is 340m/s whereas the speed of sound in moist air is 346m/s. Keep in mind that the water vapour is lighter than dry air. As we remove the moisture from air, then its density increases and the speed of sound in moist air is inversely proportional to the root of its density.

Q178. The parallel metal plates of the capacitor are separated by:

• A. Insulators✓
• B. Isolators
• C. Capacitors
• D. Resistors

Explanation: A capacitor consists of two conducting plates separated by an insulator and is used to store electric charge. If a voltage is applied to the capacitor, one plate becomes negatively charged and the other becomes positively charged. Thus, option A is correct.

Q179. A set of Atoms in an excited state decays:

• A. In any general state with lower energy✓
• B. In any state when excited by electric field
• C. In any state when excited by magnetic field
• D. None of these options are correct

Explanation: As we know, atoms are stable in the ground state, when they move to another level by gaining energy, they get excited and are ready to lose energy to get back to the ground state. This shows, generally excited state atoms decay to any of the states with lower energy. Hence,the correct option is A in any general state with lower energy which is more stable than the excited state.

Q180. A second pendulum starts its oscillation from the extreme position. What is the ratio of it's amplitude to the displacement after 7 seconds?

• A. 1:2✓
• B. 1:4
• C. 1:14
• D. Infinity

Explanation: For a simple pendulum, the ratio of the amplitude to the displacement after a given time is 1:2. This means that the amplitude of the pendulum is twice the displacement at any given point during the oscillation. In this case, the pendulum starts from the extreme position, which means the displacement at the beginning is equal to the amplitude. After 7 seconds, the displacement will be half of the amplitude, resulting in a ratio of 1:2.

Q181. A magnetic field is produced by:

• A. Moving charges✓
• B. Stationary charges
• C. Both moving and stationary charges
• D. Only ions

Explanation: A stationary charge only produce electric field where as moving charge produce electric as well as magnetic field. So option A is correct.

Q182. Magnetic flux is zero when angle between magnetic field and vector area is:

• A. Zero degree
• B. 90 degree✓
• C. 60 degree
• D. 30 degree

Explanation: The magnetic flux is a measure of the amount of magnetic field passing through a surface. When the magnetic field lines are perpendicular to the surface, the magnetic flux is zero because no field lines are passing through the surface. This occurs when the angle between the magnetic field and the surface is 90 degrees.

Q183. A body of mass 5 kg is moving with a momentum of 10 kg m/s. A force of 0.2 N acts on it in the direction of motion of the body for 10 s. The increase in it's kinetic energy is:

• A. 2.8 J
• B. 3.2 J
• C. 3.8 J
• D. 4.4 J✓

Explanation: The initial momentum of the body is given as 10 kg m/s. Using the definition of momentum, we can find the initial velocity of the body as:p = mv10 = 5vv = 2 m/sThe force acting on the body is 0.2 N and it acts for a duration of 10 seconds. Therefore, the work done by the force is:W = Fd = (0.2 N)(2 m/s)(10 s) = 4 JThe change in kinetic energy of the body is equal to the work done by the force:ΔK = W = 4 JThe final kinetic energy of the body can be calculated using the formula:Kf = (1/2)mv^2Kf = (1/2)(5 kg)(4 m/s)^2 = 40 JThe increase in kinetic energy is therefore:ΔK = Kf - Ki = 40 J - (1/2)(5 kg)(2 m/s)^2 = 4.4 JTherefore, the increase in kinetic energy of the body is 4.4 J.

Q184. The electric field intensity at a point situated 4 metres from a point charge is 200 N/C. If the distance is reduced to 2 metres, what will be the field intensity?

• A. 400 N/C
• B. 800 N/C✓
• C. 600 N/C
• D. 1200 N/C

Explanation: The electric field of a point charge at distance r is inversely proportional to r^2 orE varies as 1/r^2In the given problem, the distance is halved.Therefore,E will become 4 times the original value.The original value is 200N/C, hence the final value will be 800N/C.

Q185. When a body moves in a straight line then it's displacement concides with:

• A. Distance✓
• B. Force
• C. Acceleration
• D. Length

Explanation: Displacement is the shortest distance between the initial and final points. So, in other words, it is the distance measured along the straight lines joining the initial and final positions. And distance is the length of the total path travelled by the body between the initial and final points,Thus if the body moves along a straight line, distance will be equal to displacement.

Q186. In an electronic transition, what can the atom not emit?

• A. Gamma rays✓
• B. Infrared radiation
• C. Ultraviolet radiation
• D. Visible light

Explanation: Gamma rays are not typically emitted during electronic transition. Gamma rays have the highest energy and shortest wavelength among the electromagnetic spectrum. They are typically associated with nuclear processes, such as radioactive decay or nuclear reactions, rather than electronic transitions within atoms. So, option A is correct.

Q187. A child is swinging a swing, the minimum and maximum heights of swing are 0.75 m and 2 m respectively. The maxima velocity of the swing is:

• A. 5 m/s✓
• B. 10 m/s
• C. 15 m/s
• D. 20 m/s

Explanation: Drop in P.E = Gain in K.E mg (2-0.75) = 1 mv² v = √2g (1.25) = 5 m/s

Q188. The third law of motion explains:

• A. The effect of force
• B. The existence of a force
• C. The existence of two forces
• D. The existence of a pair of forces in nature✓

Explanation: According to the third law all the actions have reactions that’s why any force does not occur as a single it will be affected by the other force too that’s why forces are present in the form of pairs. Therefore, option D is correct.

Q189. Complete the sequence: 2, 15, 41, 80, _

• A. 111
• B. 120
• C. 121
• D. 132✓

Explanation: Multiples of 13 are being added + 13 +26 +39 so now you'll add 52

Q190. 8, 10, 14, 18, _ , 34, 50 , 66:

• A. 24
• B. 25
• C. 26✓
• D. 27

Explanation: The increasing order is +2,+4, +4, +8, +16, +16 8 + 2= 10 10 + 4= 14 14 + 4 = 8 18 + 8= 26

Q191. Blueberries cost more than strawberries.Blueberries cost less than raspberries.Raspberries cost mre than strawberries and blueberries.If the first two statements are true, the third statement is:

• A. True✓
• B. FALSE
• C. Uncertain
• D. None of these

Explanation: Explanation Because the first two statements are true, raspberries are the most expensive of the three.

Q192. The Emporium Mall has more stores than the Pakages Mall.The Amanah Mall has fewer stores than the Pakages Mall.The Emporium Mall has more stores than the Amanah Mall.If the first two statements are true, the third statement is

• A. True✓
• B. FALSE
• C. Uncertain
• D. None of these

Explanation: Explanation From the first two statements, you know that the Emporium mall has the most stores, so the Emporium Mall would have more stores than the packages Mall.

Q193. I. Car manufacturing companies have recently increased the prices of mid-sized cars. II.The Government recently increased the duty on mid-sized cars.

• A. Statement I is the cause and statement II is its effect
• B. Statement II is the cause and statement I is its effect✓
• C. Both the statements I and II are independent
• D. Both the statements I and 11 are effects of so

Explanation: Is correct as the government increased the duty on mid sized cars which is the cause due to which the companies have increased the prices of mid sized cars which is the effect

Q194. An autograph can not exist without?

• A. Actor
• B. Singer
• C. Player
• D. Pen✓

Explanation: An autograph is defined as a person's handwritten signature, mostly of someone famous among the masses. As a pen is necessary to do a signature by hand, hence it is the answer.