NCERT Class 12 MCQ Quiz Hub

1. The dimensional formula of E⃗ is:
[MLT-2A-1]
[MLT-3A-1]
[MLT-2A-2]
None of the above

2. The dimensional formula of is
[MLT-2A-1]
[ML0T-2A-1]
[ML0T-3A-1]
None of the above

3. Which of the following laws was modified by Maxwell by introducing the displacement current?
Gauss’s law
Ampere’s law
Biot-Savart’s law
None of the above

4. Choose the wave relevant to telecommunication :
ultraviolet
infrared
microwave
visible light

5. Electromagnetic waves have a speed of
(a) 3 × 105 kms-1
3 × 106 kms-1
3 × 107 kms-1
3 × 108 kms-1

6. Which of the following EMW has highest wavelength?
X-ray
ultraviolet rays
infrared rays
microwaves

7. Displacement current is due to:
the flow of electrons
the Varying electric field
the ionization of atmosphere
the flow of protons

8. Displacement current is always :
equal to conduction current
less than conduction current
greater than conduction current
the sum of current due to flow of positive and negative ions

9. EMW are produced by:
charge in uniform motion only
charge at rest only
accelerated or decelerated charge only
All the above

10. Who first demonstrated the existence of em waves?
Hertz
Maxwell
Ampere
Faraday

11. The dimensions of E/Bare same as that of:
charge
current
velocity
acceleration

12. Name the law which states that a varying electric field produces a magnetic field:
Biot-Savart’s law
Faraday’s law
Modified Ampere’s law
None of the above

13. The existence of EMW was experimentally established by :
Sir S. C. Bose
Maxwell
Marconi
Hertz

14. An EMW of v = 3 MHz passes from vacuum into dielectric medium with permittivity Er = 4, then:
Wavelength is doubled and the frequency remains unchanged
Wavelength is doubled and the frequency become half
Wavelength is halved and the frequency remains unchanged
Wavelength and frequency both remain unchanged

15. Frequency of a wave is 6 × 1015. Hz. The wave is :
Radiowave
Microwave
X-ray
Ultra violet

16. Choose the wrong statement?
Electromagnetic waves are transverse
Electromagnetic waves travel with the speed of light in free space
Electromagnetic waves are produced by accelerating charges
Electromagnetic waves travel with the same speed in all media

17. Solar radiation is :
transverse EMW
longitudinal EMW
Both of the above
None of the above

18. Ampere’s circuital law was modified by:
Laplace
Gauss
Maxwell
Hertz

19. Light Year is the unit of:
distance
time
energy
intensity of light