Electromagnetic theory miscellaneous Easy Questions and Answers | Page - 4

Electromagnetic theory miscellaneous

When a wave is propagated in a good dielectric where σ/ωε << 1 the attenuation factor and the phase shift factor are given by—

1. α = σ √ μ , β = ω √με
  2 ε
1. α = σ , β = ω √με
  2
1. α = σ √ μ √ μ , β = √ ωμε
  2ε ε 2
1. α = 1, β = 45°

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Refer synopsis

Correct Option: A

Refer synopsis

An antenna having resonant frequency f and having a Q factor of 20 can handle a bandwidth of 10 MHz then f is—

1. 10 MHz
1. 20 MHz
1. 200 MHz
1. None of these

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We have important relation of quality factor, bandwidth and cut-off frequency
Q = f ⇒ f = 20 ⇒ f = 200 MHz
BW 10 × 10⁶

where,
Q = quality factor
f = resonance frequency
BW = bandwidth

Correct Option: C

We have important relation of quality factor, bandwidth and cut-off frequency
Q = f ⇒ f = 20 ⇒ f = 200 MHz
BW 10 × 10⁶

where,
Q = quality factor
f = resonance frequency
BW = bandwidth

For a wire radiator of length equal to the wavelength of the transmitting signal. The number of loops in the radiation pattern will be—

1. 1
1. 2
1. 3
1. 4

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Wire radiator behaves in same way as two isotropic sources separated by 'λ' distance. So it will have 4 radiators.

Correct Option: D

Wire radiator behaves in same way as two isotropic sources separated by 'λ' distance. So it will have 4 radiators.

The electric field component of a uniform plane electromagnetic wave propagating in the y-direction in a lossless medium will satisfy the equation—

1. ∂²E_y = με ∂²E_y
  ∂y² ∂t²
1. ∂²E_y = με ∂²E_y
  ∂y² ∂t²
1. ∂²E_x = με ∂²E_x
  ∂y² ∂t²
1. √E²x +E²z = √ μ
  √H²_x + H²_z ε
1. Both A and D

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For uniform plane wave phase and magnitude remains constant in the plane normal to the propagation and changes with the direction of propagation. Hence alternative (A) and (D) as correct option.

Correct Option: E

For uniform plane wave phase and magnitude remains constant in the plane normal to the propagation and changes with the direction of propagation. Hence alternative (A) and (D) as correct option.

In a reflex Klystron oscillator—

1. The maximum possible efficiency is about 58%.
1. The frequency of oscillation varies linearly with the reflector voltage.
1. The power output varies continuously with reflector voltage.
1. The power output is maximum at fixed frequency.
1. Both A and B

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NA

Correct Option: E

NA