Punjab Physics 2015 Paper 1 — Solved MCQs

Question 1

The electrostatic force of repulsion between two electrons at a distance 1m is:

Accepted Answer

D. 2.3x10-30N — The explanation will be added soon!

Question 2

A charged conductor has charge on its?

Accepted Answer

B. Outer-surface — Excess charge on a conductor resides on the outer surface due to electrostatic repulsion, as mentioned above. This ensures that the electric field inside the conductor is zero and the charges are in a stable equilibrium state.

Question 3

Ampere second stands for the unit of:

Accepted Answer

A. Charge — The unit of charge is the coulomb (C), but it can also be expressed as ampere-second (A·s). This is because 1 coulomb is equivalent to 1 ampere of current flowing for 1 second. So, an ampere-second (A·s) is a measure of the quantity of electricity transferred by a current of 1 ampere in 1 second.

Question 4

The relation between current I and angle of deflection θ in a moving coil galvanometer is:

Accepted Answer

A. I α θ — In a moving coil galvanometer, the deflection of the coil is proportional to the current passing through it. Therefore, the current (I) is proportional to the angle of deflection (theta).

Question 5

Lorentz force is given by:

Accepted Answer

D. Option D — The explanation will be added soon!

Question 6

Which one of the following is not present in an A.C generator?

Accepted Answer

B. Commutator — A commutator is a component found in DC generators, not in AC generators. It consists of a rotating switch or contacts that reverse the direction of the current in the armature coils every half-turn, converting the alternating current induced in the armature coils into direct current.

Question 7

The core of transformer is laminated to reduce:

Accepted Answer

C. Eddy current loss — Laminating the core of a transformer is primarily done to reduce eddy current loss. Eddy currents are induced currents that flow in the core material due to the changing magnetic field. These currents lead to energy loss in the form of heat, which is minimized by laminating the core into thin layers perpendicular to the direction of the magnetic field.

Question 8

In RLC parallel circuit the resonance frequency is:

Accepted Answer

D. Option D — The explanation will be added soon!

Question 9

Electromagnetic waves emitted from radio antenna are:

Accepted Answer

C. Transverse — Electromagnetic waves, including radio waves, are transverse waves. In a transverse wave, the oscillations of the medium (electric and magnetic fields in this case) are perpendicular to the direction of wave propagation. This characteristic allows electromagnetic waves to travel through vacuum, as they do not require a medium for propagation.

Question 10

Minority carriers in p-type substances are:

Accepted Answer

B. Electrons — In p-type semiconductor materials, which are doped with acceptor impurities, the majority carriers are "holes." Holes are essentially vacancies in the valence band created when electrons from the valence band are excited to the conduction band. These holes act as positively charged carriers that can move through the material.

Question 11

The gain of non-inverting amplifire is:

Accepted Answer

D. Option D — The explanation will be added soon!

Question 12

The common emitter current amplification factor β is given by:

Accepted Answer

D. Option D — The explanation will be added soon!

Question 13

In compton effect the photon behaves as a:

Accepted Answer

B. Particle — In the Compton effect, the photon behaves as a particle. The interaction between the X-ray photon and the electron is described by the transfer of energy and momentum as if the photon were a discrete particle.

Question 14

The binding energy per nucleon is maximum for:

Accepted Answer

B. Iron — Iron (specifically, iron-56) has the highest binding energy per nucleon of all the elements. This means that, on average, each nucleon (proton or neutron) in an iron nucleus is bound more tightly than in any other element. This is why iron is often referred to as the "peak of stability."

Question 15

Gamma rays from cobalt-60 are used for the treatment of:

Accepted Answer

B. Cancer — Gamma rays from cobalt-60 are used in radiation therapy for the treatment of cancer. The high-energy gamma rays can penetrate tissue and damage the DNA of cancer cells, leading to their destruction.

Question 16

The radius of 10th orbit in hydrogen atom is:

Accepted Answer

D. 53nm — The explanation will be added soon!

Question 17

In an electronic transition atom cannot emit:

Accepted Answer

D. γ-radiations — Atoms do not emit gamma (γ) radiation during electronic transitions. Gamma radiation is a high-energy electromagnetic radiation emitted from the atomic nucleus during nuclear transitions. Electronic transitions involve changes in the electron cloud surrounding the nucleus and do not result in the emission of gamma radiation.

Question 18

1/C_eq = 1/C_1 + 1/C_2 + 1/C_3 + ... + 1/C_n

Accepted Answer

A. Series — Correct option is A.For capacitors in series, the total capacitance can be found by adding the reciprocals of the individual capacitance's, and taking the reciprocal of the sum.

Punjab Physics 2015 Paper 1 — Solved Past Paper with Answers

More Punjab / UHS Solved Papers