# Class 12 Physics Model Paper MCQs Test

FBISE Federal Board Class 12 Physics Model Paper 2020 MCQs Test. Do as much practice as you can so that you get good marks in the final exams.

Class 12 Physics MCQs Tests

### Class 12 Physics Model Paper MCQs Test

/17
5

Class 12 Physics
Model Paper 2020
Practice MCQs Test

1 / 17

1. The velocity at which the relativistic length of a body reduces to half of its original length is:

2 / 17

2. If input power and output power of an electric motor are 540 W and 382 W respectively. Then the efficiency is:

3 / 17

3. The half-life of 38Sr91 is 9.70 hours. What is the decay constant?

4 / 17

4. A consequence of Einstein’s theory of relativity is:

5 / 17

5. The ratio of minimum to maximum wavelength in Balmer series is:

6 / 17

6. At what frequency an inductor of 1H will have a reactance of 500 ohms?

7 / 17

7. When a battery of emf “E” and internal resistance “r” is connected across external resistance R, the power consumed in R is maximum when r⁄R is:

8 / 17

8. Two identical circular loops A and B of a metal wire are placed on a table without touching each other. Loop A carries a current which increases with time. In response, the loop B will:

9 / 17

9. A closed surface encloses two equal and opposite charges. The net flux through the surface is:

10 / 17

10. The speed of electrons in the 2nd Bohr orbit is:

11 / 17

11. Photon A has twice the energy to that of photon B. The ratio of momentum of A and B is PA/PB = ______

12 / 17

12. 1Henry = _________:

13 / 17

13. The constant α of a transistor is 0.95. What would be the change in the collector current corresponding to a change of 0.4mA in the base current in a common-emitter arrangement?

14 / 17

14. Two charges q1 and q2 are placed in a vacuum at a distance d and force between them is F. If a medium of relative permittivity 4 is introduced between them, then the new force will be:

15 / 17

15. A wire has a resistance of 12Ω. It is bent in the form of a circle. The effective resistance between the two points on any diameter of the circle is:

16 / 17

16. Two charges q1 and q2 are placed in a vacuum at a distance d and force between them is F. If a medium of relative permittivity 4 is introduced between them, then the new force will be:

17 / 17

17. If the forward voltage in a diode is increased, the width of the depletion region: