MCQs on Electromagnetic Waves

MCQs on Electromagnetic Waves

Q: Electromagnetic waves are produced by

1. A static charge
2. An accelerated charge
3. A moving charge
4. Charged particles

Answer: (b) An accelerated charge

Q: In electromagnetic waves the phase difference between electric field vector and magnetic field vector is

1. zero
2. π/2
3. π
4. π/3

Answer: (a) zero

Q: In an electromagnetic wave in free space, the root mean square value of the electric field is 6 V/m. The peak value of the magnetic field is

1. 2.83 x 10^-8 T
2. 1.51 x 10^-8 T
3. 0.80 x 10^-8 T
4. 4 x 10^-8 T

Answer: (a) 2.83 x 10^-8 T

Q: Which of the following can be used to produce a propagating electromagnetic wave?

1. Charge moving at a constant speed
2. Chargeless particle
3. Stationary charge
4. An accelerating charge

Answer: (d) An accelerating charge

Q: To which part of the spectrum does EM waves belong if the energy of the wave is of the order of 15 KeV.

1. X rays
2. Infrared rays
3. Ultraviolet rays
4. Gamma rays

Answer: (a) X rays

Q: The ratio of the amplitude of the magnetic field to the amplitude of the electric field for electromagnetic wave propagation in a vacuum is equal to

1. Unity
2. Speed of light in vacuum
3. Reciprocal of the speed of light in vacuum
4. The ratio of magnetic permeability to electrical susceptibility in a vacuum.

Answer: (c) Reciprocal of the speed of light in vacuum

Q: Which properties amount the following is false about electromagnetic waves?

1. The energy in an electromagnetic wave is divided equally between electric and magnetic vectors.
2. Both electric and magnetic field vectors are parallel to each other and perpendicular to the direction of propagation of the wave.
3. These waves do not require any material medium for propagation
4. Both electric and magnetic field vectors attain the maxima and minima at the same place and the same time

Answer: (b) Both electric and magnetic field vectors are parallel to each other and perpendicular to the direction of propagation of the wave.

Q: Which of the following rays are not electromagnetic waves?

1. Gamma rays
2. Beta rays
3. Heat rays
4. X rays

Answer: (b) Beta rays