Kpk Physics 2015 — Solved MCQs

Question 1

In a transistor, collector current is controlled by

Accepted Answer

B. base current — In a transistor, the collector current (IC) is controlled by the base current (IB).

Question 2

The mass defect (in atomic mass unit) of the nucleus is_

Accepted Answer

B. .None of these — The formula to calculate the mass defect (Δm\Delta mΔm) of a nucleus is given by:Δm=Z⋅mp+N⋅mn−M

Question 3

Which of the given quantities remain constant in Step up transformer?

Accepted Answer

C. Power — In a step-up transformer, the voltage increase and power conservation remain constant, while voltage, current, impedance, and current density change.

Question 4

A one microfarad capacitor of a TV is 4000 V potential

Accepted Answer

B. 4x10-7J — The question refers to a capacitor in a TV that has a capacitance of 1 microfarad (µF) and is charged to a potential difference, or voltage, of 4000 volts (V).The energy (E) stored in a capacitor can be calculated using the formula: E =1/2 CV2where:E is the energy stored in the capacitor, measured in joules (J)C is the capacitance of the capacitor, measured in farads (F)V is the potential difference across the capacitor, measured in volts (V)Substituting the given values into the formula, we get:E = 1/2 (1µF) (4000V)2Please note that 1 µF = 1e-6 F. So, the calculation becomes: E = 1/2 (1µF * 1e-6 F ) (4000V)2 = 4x10-7J

Question 5

When a wire is stretched and its radius becomes

Accepted Answer

D. 8R

Question 6

A coil current changes from 244M A in 0.05sec. If average induced emf is 8v, then coefficient of self inductance.

Accepted Answer

B. 1.64×10-6H — Using formula:ε=−LΔt/ΔI

Question 7

Frequency of X-rays depends upon

Accepted Answer

D. Both B and C — The frequency of X-rays depends on both the nature of the target material and the accelerating voltage applied in an X-ray tube. So, the correct answer is: Both B and C

Question 8

A shunt resistance used to convert it into_ parallel t to the galvanometer is

Accepted Answer

A. Avometer — A shunt resistance is used to convert a galvanometer into an ammeter. An ammeter is used to measure electric current. Therefore, the answer is "avometer."

Question 9

Bottom quark carries charge_

Accepted Answer

B. - 1/3 * e — The bottom quark carries an electric charge of −1/3e-, where e is the elementary charge. This charge is negative and one-third of the elementary charge.

Question 10

A 100 watt bulb is operated by 200 volts, the current flowing through the bulb is_

Accepted Answer

D. D.0.5amp — We need to find the resistance of the bulb. We can use the formula for power in terms of voltage and resistance:P=V2/RRearranging for resistance:R=V2/RNow, we can use Ohm's law to find the current (I):I=V/R So ,the current flowing through the bulb is 0.5 A

Question 11

The unit of permeability of free space is

Accepted Answer

A. (Tm)/A — The unit of permeability of free space in terms of tesla (T) is tesla per ampere per meter (T⋅m/A).

Question 12

The practical application for the phenomenon mutual induction is_

Accepted Answer

D. ACGenerator — AC generators, also known as alternators, is practical application of mutual induction.

Question 13

If the of a free electron doubles, its de-Broglie wavelength changes by the factor_

Accepted Answer

C. 1/2 — The factor by which the de Broglie wavelength changes is 1/2

Question 14

The electric field as a potential gradient can be expressed as_

Accepted Answer

C. (Delta*v)/(Delta*r) — The electric field (E) as a potential gradient (V) can be expressed using the formula:E=−dV/dx

Question 15

The circuit in which current phase voltage are in phase , the power factor is_

Accepted Answer

A. 1 — In a circuit where voltage and current are in phase, the power factor is 1

Question 16

The ability to resist bending is called_

Accepted Answer

B. B.Stiffness — The ability to resist bending is called "stiffness" or "flexural rigidity.

Question 17

The mathematical expression for self inductance coil is given by_

Accepted Answer

B. L=μ⋅N2⋅A​/l — Formula:L=μ⋅N2⋅A​/l

Question 18

tance of a capacitor is givehibate. Windo

Accepted Answer

D. X_{c} = 1/W_{o}

Kpk Physics 2015 — Solved Past Paper with Answers

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