Electromagnetic Waves Easy Questions and Answers | Page - 1

Electromagnetic Waves

The electric and magnetic field of an electromagnetic wave are

1. in opposite phase and perpendicular to each other
1. in opposite phase and parallel to each other
1. in phase and perpendicular to each other
1. in phase and parallel to each other.

View Hint View Answer Discuss in Forum

Variation in magnetic field causes electric field and vice-versa. In electromagnetic waves, Ê ⊥ B̂ Both Ê and B̂are in the same phase.
In electromagnetic waves
E = E₀ sin(ωt - kx)
B = B₀ sin(ωt - kx)
The electromagnetic waves travel in the direction of
(→
E →
B)

Correct Option: C

Variation in magnetic field causes electric field and vice-versa. In electromagnetic waves, Ê ⊥ B̂ Both Ê and B̂are in the same phase.
In electromagnetic waves
E = E₀ sin(ωt - kx)
B = B₀ sin(ωt - kx)
The electromagnetic waves travel in the direction of
(→
E →
B)

Which of the following statement is false for the
properties of electromagnetic waves?

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

View Hint View Answer Discuss in Forum

Electromagnetic waves are the combination of mutually perpendicular electric and magnetic fields. So, option (c) is false.

Correct Option: C

Electromagnetic waves are the combination of mutually perpendicular electric and magnetic fields. So, option (c) is false.

The electric field part of an electromagnetic wave in a medium is represented by E_x=0;
= E_y = 2.5 N cos 2π × 10⁶ rad - 1 π × 10^-2 rad x ;
C m s

E_{z_{= 0. The wave is :}}

1. moving along x direction with frequency 10⁶ Hz and wave length 100 m.
1. moving along x direction with frequency 10⁶ Hz and wave length 200 m.
1. moving along – x direction with frequency 10⁶ Hz and wave length 200 m.
1. moving along y direction with frequency 2π × 10⁶ Hz and wave length 200 m.

View Hint View Answer Discuss in Forum

Comparing with the equation of wave.
E_y = E₀ cos (ωt – kx)
ω = 2 πf = 2π × 10⁶
∴ f = 10⁶ Hz
2π/λ = K
= π × 10^-2 m^-1, λ = 200 m

Correct Option: B

Comparing with the equation of wave.
E_y = E₀ cos (ωt – kx)
ω = 2 πf = 2π × 10⁶
∴ f = 10⁶ Hz
2π/λ = K
= π × 10^-2 m^-1, λ = 200 m

The velocity of electromagnetic radiation in a medium of permittivity ε_{0_{and permeability µ_{0_{is given by}}}}

1. ε₀
  μ₀
1. √ε₀μ₀
1. 1
  ε₀μ₀
1. μ₀
  ε₀

View Hint View Answer Discuss in Forum

The velocity of electromagnetic radiation in a medium of permittivity
∊₀ and permeability µ₀ is is equal to
√μ₀∊₀

Correct Option: C

The velocity of electromagnetic radiation in a medium of permittivity
∊₀ and permeability µ₀ is is equal to
√μ₀∊₀

The electromagnetic radiations are caused by

1. a stationary charge
1. uniformly moving charges
1. accelerated charges
1. all of above

View Hint View Answer Discuss in Forum

A stationary charge produces electric field only; an uniformly moving charge produces localised electromagnetic field; an accelerated charge produces electromagnetic radiations.

Correct Option: C

A stationary charge produces electric field only; an uniformly moving charge produces localised electromagnetic field; an accelerated charge produces electromagnetic radiations.