Electromagnetic Field Theory MCQ Questions & Answers

Section 1 Section 2 Section 3 Section 4

81.
The displacement current can be represented as

A. $${i_d} = {\mu _0}\frac{{d{\phi _E}}}{{dt}}$$

B. $${i_d} = { \in _0}\frac{{d{\phi _E}}}{{dt}}$$

C. $${i_d} = {\mu _0}\frac{{d{\phi _B}}}{{dt}}$$

D. $${i_d} = { \in _0}\frac{{d{\phi _B}}}{{dt}}$$

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82.
What is the value of the magnetic vector potential due to an infinitesimally small current element, evaluated at infinite distance from it?

A. Infinity

B. Unity

C. Zero

D. Any number between zero and infinity depending on the strength of the current element

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83.
A steel pipe is constructed of a material for which µ_r = 200 and σ = 5 × 10⁶ mho/m. The outer and inner radii are 8 and 6 mm respectively and the length is 80 m. If the total current carried by the pipe is 2cos10⁴πt A,Then the skin depth will be

A. 0.225 × 10^-3 m

B. 0.300 × 10^-3 m

C. 0.352 × 10^-3 m

D. 0.125 × 10^-3 m

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84.
If the short circuit and open circuit impedance of a line are 5 Ω and 20 Ω respectively the characteristic impedance is given by

A. 100 Ω

B. 10 Ω

C. 15 Ω

D. 10000 Ω

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85.
The characteristic impedance of a co-axial cable depends on diameter of

A. inner conductor

B. outer conductor

C. both inner & outer conductors

D. none of these

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86.
In general attenuation per unit length in a coaxial cable:

A. increases with frequency

B. decreases with frequency

C. remains constant with frequency

D. depends upon the type of coaxial cable. It can either increase or decrease

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87.
What would be the standing wave ratio (SWR) for a line with reflection coefficient equal to 0.49?

A. 0.01

B. 2.12

C. 2.921

D. 3.545

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88.
When a plane electromagnetic wave is incident normally on the boundary between two lossless dielectric media, the transmission coefficient for magnetic field intensity $$\overrightarrow H $$ is

A. $$\frac{{{n_1} - {n_2}}}{{{n_1} + {n_2}}}$$

B. $$\frac{{{n_2} - {n_1}}}{{{n_1} + {n_2}}}$$

C. $$\frac{{2{n_2}}}{{{n_1} + {n_2}}}$$

D. $$\frac{{2{n_1}}}{{{n_1} + {n_2}}}$$

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89.
The potential at the centroid of an equilateral triangle of side $$r\sqrt 3 $$ due to three equal positive point charges each of value q and placed at the vertices of the triangle would be:

A. $$\frac{q}{{2\pi { \in _0}r}}$$

B. $$\frac{{\sqrt {3q} }}{{8\pi { \in _0}r}}$$

C. $$\frac{{3q}}{{4\pi { \in _0}r}}$$

D. Zero

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90.
Consider the following statements:
For a 10 m long common power line connecting a switch to a light bulb
1. It is distributed circuit
2. Time delay for propagation through it is negligible
3. It is in the form of a shielded coaxial cable of circular cross-section
4. As the intensity of the lamp varies, input impedance of this line also changes
Which of the above statements is/are correct?

A. 1 only

B. 1 and 2

C. 2 and 3

D. 2 and 4

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Electromagnetic Field Theory MCQ Questions & Answers | ECE

81. The displacement current can be represented as

Answer & Solution

82. What is the value of the magnetic vector potential due to an infinitesimally small current element, evaluated at infinite distance from it?

Answer & Solution

83. A steel pipe is constructed of a material for which µr = 200 and σ = 5 × 106 mho/m. The outer and inner radii are 8 and 6 mm respectively and the length is 80 m. If the total current carried by the pipe is 2cos104πt A,Then the skin depth will be

Answer & Solution

84. If the short circuit and open circuit impedance of a line are 5 Ω and 20 Ω respectively the characteristic impedance is given by

Answer & Solution

85. The characteristic impedance of a co-axial cable depends on diameter of

Answer & Solution

86. In general attenuation per unit length in a coaxial cable:

Answer & Solution

87. What would be the standing wave ratio (SWR) for a line with reflection coefficient equal to 0.49?

Answer & Solution

88. When a plane electromagnetic wave is incident normally on the boundary between two lossless dielectric media, the transmission coefficient for magnetic field intensity $$\overrightarrow H $$ is

Answer & Solution

89. The potential at the centroid of an equilateral triangle of side $$r\sqrt 3 $$ due to three equal positive point charges each of value q and placed at the vertices of the triangle would be:

Answer & Solution

Answer & Solution

Read More Section(Electromagnetic Field Theory)

81.
The displacement current can be represented as

82.
What is the value of the magnetic vector potential due to an infinitesimally small current element, evaluated at infinite distance from it?

83.
A steel pipe is constructed of a material for which µ_r = 200 and σ = 5 × 10⁶ mho/m. The outer and inner radii are 8 and 6 mm respectively and the length is 80 m. If the total current carried by the pipe is 2cos10⁴πt A,Then the skin depth will be

84.
If the short circuit and open circuit impedance of a line are 5 Ω and 20 Ω respectively the characteristic impedance is given by

85.
The characteristic impedance of a co-axial cable depends on diameter of

86.
In general attenuation per unit length in a coaxial cable:

87.
What would be the standing wave ratio (SWR) for a line with reflection coefficient equal to 0.49?

88.
When a plane electromagnetic wave is incident normally on the boundary between two lossless dielectric media, the transmission coefficient for magnetic field intensity $$\overrightarrow H $$ is

89.
The potential at the centroid of an equilateral triangle of side $$r\sqrt 3 $$ due to three equal positive point charges each of value q and placed at the vertices of the triangle would be: