NCERT Class 12 Chapter 8 Physics Electromagnetic Waves MCQ

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1. The electromagnetic waves do not transport

A. energy

B. charge

C. momentum

D. information

2. Which of the following has minimum wavelength?

A. Blue light

B. γ-rays

C. infrared rays

D. microwave

3. Which of the following has/have zero average value in a plane electromagnetic wave?

A. Both magnetic and electric fields

B. Electric field only

C. Magnetic field only

D. None of these

4. The speed of electromagnetic waves in free space

CBSE Class12 Physics Electric Charges (4Q)

A. permeability, permittivity

B. coercivity, permeability

C. permeability, susceptibility

D. permittivity, permeability

5. The polarisation of electromagnetic wave is in

A. the directions of electric and magnetic field

B. the directions of electric field

C. the direction of magnetic field

D. can not be polarized

6. Which of the following has maximum penetrating power?

A. Ultraviolet radiation

B. Microwaves

C. γ-rays

D. Radio waves

7. Which of the following laws was modified by Maxwell by introducing the displacement current?

A. Gauss’s law

B. Ampere’s law

C. Biot-Savart’s law

D. None of these

8. Which region in the electromagnetic spectrum will have the highest speed?

A. Radio

B. Visible

C. All the regions have same speed

D. Microwaves

9. The current in the electric circuit which arises due to flow of electrons in the connecting wires of the circuit in a defined closed path is called

A. alternating current

B. direct current

C. conduction current

D. displacement current

10. Electromagnetic waves travelling in a medium having relative permeability μr = 1.3 and relative permittivity Er = 2.14. The speed of electromagnetic waves in medium must be

A. 1.8 × 108 ms-1

B. 1.8 × 104ms1

C. 1.8 × 106ms1

D. 1.8 × 10² ms-1

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11. Which of the following has maximum penetrating power?

A. Ultraviolet radiation

B. Microwaves

C. γ-rays

D. Radio waves

12. Which region in the electromagnetic spectrum has the highest frequency?

A. Frequency is same for the complete spectrum

B. Gamma Radiation Region

C. Radio

D. Visible

13. If a variable frequency ac source connected to a capacitor then with decrease in frequency, the displacement current will

A. increase

B. decrease

C. remain constant

D. first decrease then increase

14. In electromagnetic waves the phase difference between electric and magnetic field vectors are

A. zero

B. π4

C. π2

D. π

15. The source of electromagnetic waves can be a charge

A. moving with a constant velocity.

B. moving in a circular orbit

C. at rest.

D. none of these.

16. Electromagnetic waves constitute of

A. Electric and magnetic field varying in space and time sinusoidally and propagating through space such that the two fields are at 60 degrees to the direction of propagation.

B. Electric and magnetic field varying in space and time sinusoidally and propagating through space such that the two fields are perpendicular to the direction of propagation.

C. Electric and magnetic field varying in space and time tangentially and propagating through space such that the two fields are perpendicular to the direction of propagation

D. Electric and magnetic field varying in space and time tangentially and propagating through space such that the two fields are perpendicular to the direction of propagation.

17. Displacement current goes through the gap between the plates of a capacitor when the charge on the capacitor

A. is changing with time

B. decreases

C. does not change

D. decreases to zero

18. The quantity μ0ε0−−−−√ represents

A. speed of sound

B. speed of light in vacuum

C. speed of e.m.w

D. inverse of speed of light in vacuum

19. Which of the following has maximum penetrating power?

A. Ultraviolet radiation

B. Microwaves

C. γ-rays

D. Radio waves

20. In electromagnetic waves the ratio of amplitudes of electric field and magnetic field is equal to

A. (E₀ / 2B₀) = c

B. (E₀ / B₀)^1/2 = c

C. (2E₀ / B₀) = c

D. (E₀ / B₀) = c

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21. An electron oscillating with a frequency of 3 × 10⁶ Hz, would generate

A. X-rays

B. ultraviolet rays

C. radio waves

D. microwaves

22. In electromagnetic wave if ue and um are mean electric and magnetic energy densities respectively, then CBSE Class12 Physics Electromagnetic Waves (22Q))

CBSE Class12 Physics Electromagnetic Waves (22Q))

A. (a)

B. (b)

C. (c)

D. (d)

23. What is the ratio of the speed of infrared and ultraviolet rays in a vacuum?

A. 1:5

B. 2:1

C. 1

D. 0

24. Which statement is true about electromagnetic waves?

A. Electromagnetic waves are longitudinal in nature

B. Electromagnetic waves can travel through vacuum

C. Velocity of electromagnetic waves is 3 X 10⁹ m/s

D. Ratio of electric field and magnetic field in electromagnetic field is 2E_rms / B_rms

25. Select the wrong statement. EM waves

A. are transverse in nature.

B. travel in free space at a speed of light.

C. are produced by accelerating charges.

D. travel in all media with same speed