12th class (Fsc) Physics unit 8 MCQs
chapter 8 MCQs 12th Class physics
Dawn of Modern Physics:
1. The value of Wien’s constant is:
a. 5.67×10-8 mK
b. 2.9×10-3 mK
c. 5.67×10-8 mm-2K-4
d. 2.9×10-3 mK
2. The maximum kinetic energy of emitted photo electrons depends upon:
a. Metal surface
b. The intensity of incident light
c. Both frequency of incident light and metal surface
d. Frequency of the incident light
3. The minimum energy required to create pair production is:
a. 1.02 eV
b. 1.02 keV
c. 1.02 J
d. 1.02 MeV
4. Using relativistic effects the location of an air craft after an hr fight can be predicated about:
a. 760m
b. 20m
c. 780m
d. 50m
5. All motions are:
a. Relative
b. Absolute
c. Variable
d. Uniform
6. Who explained the photo electric effect?
a. Henry
b. Max plank
c. Rutherford
d. Einstein
7. The number of electrons emitted depends upon:
a. Frequency of incident light
b. Colour of target surface
c. Intensity of incident light
d. Shape of surface
8. Internal frame is a frame in which:
a. 3rd law holds
b. 1st law holds
c. Kelvin’s law holds
d. 2nd law holds
9. 0.1 kg mass will be equivalent to the energy:
a. 9×1016 Joules
b. 5×108 Joules
c. 9×1015 Joules
d. 6×1019 Joules
10. Potassium Cathodes in photocell emit electrons for a light:
a. Ultra-violet
b. Visible
c. X-rays
d. Infra-red
11. Einstein was awarded Nobel prize in physics in:
a. 1918
b. 1905
c. 1921
d. 1911
12. If an object moves with speed of light its mass will be:
a. Minimum
b. Zero
c. Infinity
d. Maximum
13. In 1905, the special theory of relativity was proposed by:
a. Maxwell
b. Einstein
c. De-Broglie
d. Bohr
14. The unit of work function is:
a. Farad
b. eV
c. Hertz
d. volt
15. The stopping potential for a certain metal is 10 volts. Thus work function for the function for the cathode is:
a. 1.6×10-19 J
b. 10 J
c. 1.6×10-20 J
d. 1.6×10-18 J
16. The velocity at which relativistic length of a body reduce to half of its original length in:
17. The mass of object will be doubled at speed:
a. 3.6×108 m/s
b. 2.6×108 m/s
c. 0.6×108 m/s
d. 1.6×108 m/s
18. The value of Stefan’s constant is:
a. 5.67×10-10wm-2k-4
b. 5.67×10-6wm-6k-6
c. 5.67×10-4wm-2k-4
d. 5.67×10-8wm-2k-4
19. Number of electrons emitted in photoelectric effect depend upon:
a. Energy of incident light
b. IP intensity of incident light
c. Wavelength of incident of light
d. Frequency of incident light
20. Compton’s shift in wave length (Δλ) is zero, when scattered angle of photon is:
a. 0o
b. 90o
c. 45o
d. 180o
21. The length of a rod will becomes half at the speed:
a. 3.6×107 ms-1
b. 2.6×107 ms-1
c. 3.6×108 ms-1
d. 2.6×108 ms-1
22. If an object moves with speed of light, its mass will be:
a. Infinity
b. Zero
c. Minimum
d. Maximum
23. Compton effect proves:
a. Dual natural of particle
b. Wave nature of radiation
c. Particle nature of radiations
d. Wave nature of particle
24. Earth orbital speed is:
a. 30 km/s
b. 10 km/s
c. 40 km/s
d. 20 km/s
25. The quantity h/moc has the dimensions of:
a. Mass
b. Length
c. Energy
d. Time