Electromagnetic Field Theory MCQ Questions & Answers

71

When a plane wave traveling in free space is incident normally on a medium having ε_r = 4.0, the fraction of power transmitted into the medium is given by

A) $$\frac{8}{9}$$ B) $$\frac{1}{2}$$ C) $$\frac{1}{3}$$ D) $$\frac{5}{6}$$

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Answer & Solution

Answer: Option A

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72

Insertion loss is defined by

A) -20 Log₁₀ (1 - |r|²) B) -10 Log₁₀ |r| C) -10 Log₁₀ (1 - |r|²) D) -10 Log₁₀ (1 + |r|²)

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Answer: Option C

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73

A TEM wave impinges obliquely on a dielectric-dielectric boundary with ∈_r₁ = 2 and ∈_r₂ = 1. The angle of incidence for total reflection is:

A) 30° B) 60° C) 45° D) 90°

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Answer: Option C

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74

Which one of these equation is not Maxwell's equation for a static electromagnetic field in a linear homogeneous medium state?

A) ∇.B = 0 B) ∇ × D = 0 C) $$\oint {{\text{D}}.{\text{ds}} = {\text{Q}}} $$ D) ∇²A = µ₀J

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Answer & Solution

Answer: Option D

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75

In the following figure, the transmitter T_x sends a wideband modulated RF signal via a coaxial cable to the receiver R_x. The output impedance Z_T of T_x the characteristic impedance Z₀ of the cable and the input impedance Z_R or R_x are all real.
Which one of the following statements is True about the distortion of the received signal due to impedance mismatch?
Electromagnetic Field Theory mcq question image

Electromagnetic Field Theory mcq question image

A) The signal gets distorted if Z_R ≠ Z₀, irrespective of the value of Z_T B) The signal gets distorted if Z_T ≠ Z₀, irrespective of the value of Z_R C) Signal distortion implies impedance mismatch at both ends Z_T ≠ Z₀ and Z_R ≠ Z₀ D) Impedance mismatches don't result in signal distortion but reduce power transfer efficiency

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Answer & Solution

Answer: Option C

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76

The equation ∇.J = 0 is known as:

A) Poisson's equation B) Laplace equation C) Continuity equation D) Maxwell equation

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Answer & Solution

Answer: Option C

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77

A plane electromagnetic wave in a free space is represented by an equation.

A) $${\Delta ^2}\overrightarrow E - \mu { \in _0}\frac{{{\partial ^2}\overrightarrow B }}{{\partial {t^2}}} = 0$$ B) $${\Delta ^2}\overrightarrow E - {\mu _0}{ \in _0}\frac{{{\partial ^2}\overrightarrow B }}{{\partial {t^2}}} = 0$$ C) $${\Delta ^2}\overrightarrow E - {\mu _0}{ \in _0}\frac{{{\partial ^2}\overrightarrow E }}{{\partial {t^2}}} = 0$$ D) $${\Delta ^2}\overrightarrow E - \mu \sigma \frac{{{\partial ^2}\overrightarrow E }}{{\partial t}} + \mu \in \frac{{{\partial ^2}\overrightarrow E }}{{\partial {t^2}}} = 0$$

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Answer & Solution

Answer: Option C

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78

A transmission line having characteristic impedance 'Z_t' of varying length in series with a load impedance 'Z_L' appears in a Smith Chart on:

A) Constant Resistance Circle B) Constant VSWR Circle C) Constant Reactance Circle D) All of the above

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Answer: Option B

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79

When the target lies at such a distance from the radar that the radar receives the echo while it is transmitting, the target is said to be

A) At an ambiguous range B) At a blind range C) In the closed vicinity of clutter D) None of these

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Answer: Option B

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80

What is the magnetic field intensity vector $$\overrightarrow H $$ between two parallel sheets with separation 'd' along z-axis both sheets carrying surface current $$\overline k = {k_y}{\overline a _y}?$$

A) $$ - {k_y}{\overline a _y}$$ B) $$ + {k_y}{\overline a _y}$$ C) $$ - {k_y}{\overline a _x}$$ D) Zero

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Answer: Option D

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Electromagnetic Field Theory MCQ Questions & Answers | ECE