Electromagnetic Waves Easy Questions and Answers | Page - 3

Electromagnetic Waves

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.

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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

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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 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.

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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)

If ^→_E and ^→_B represent electric and magnetic field vectors of the electromagnetic waves, then the direction of propagation of the waves will be along

1. ^→_B > ^→_E
1. ^→_E
1. ^→_B
1. ^→_E < ^→_B

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Direction of propagation of electro-magnetic waves is perpendicular to Electric field and Magnetic field. Hence, direction is given by vector

Correct Option: D

Direction of propagation of electro-magnetic waves is perpendicular to Electric field and Magnetic field. Hence, direction is given by vector

The electromagnetic radiations are caused by

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

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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.