# Electromagnetic Theory MCQ Questions & Answers

Electromagnetic Theory MCQs : This section focuses on the "Electromagnetic Theory". These Multiple Choice Questions (MCQs) should be practiced to improve the Electromagnetic Theory skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.

Question 1

Identify which of the following is not a transmission line?

A. Telephone lines
B. Power transmission
C. Underground cables
D. Cavity resonators

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Question 2

The open wire transmission line consists of

A. Conductor
B. Dielectric
C. Both conductor and dielectric
D. Either conductor or dielectric

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Question 3

Telephone lines and power lines are open wire transmission lines. State true/false.

A. True
B. False

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Question 4

The cable transmission line consists of

A. Conductors
B. Insulators
C. Insulated conductors
D. Insulated conductors with dielectric

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Question 5

The coaxial cable consists of

A. Conductors
B. Insulators
C. Conductor with dielectric
D. Two conductors with dielectric

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Question 6

The coaxial cable are used in

A. Telephone cables transmission
B. Power transmission
C. Television signal transmission
D. Short wave transmission

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Question 7

Identify which is not a type of waveguide.

A. Rectangular
B. Circular
C. Cylindrical
D. Cavity resonator

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Question 8

The range of frequencies handled by the waveguides is in

A. Hz
B. KHz
C. MHz
D. GHz

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Question 9

The range of frequencies operated by the coaxial cables is in

A. Hz
B. KHz
C. MHz
D. GHz

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Question 10

The cut off frequency for waveguide operation is

A. 2 MHz
B. 6 GHz
C. 4 MHz
D. 6 MHz

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Question 11

The highest means of communication is

A. Internet
B. Telephone
C. Television
D. Radio

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Question 12

In free space, the charge carriers will be

A. 0
B. 1
C. 100
D. Infinity

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Question 13

In free space, which parameter will be unity?

A. Permittivity
B. Absolute permittivity
C. Relative permittivity
D. Permeability

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Question 14

Which parameter is unity in air medium?

A. Permittivity
B. Absolute permittivity
C. Relative permittivity
D. Permeability

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Question 15

The conductivity in free space medium is

A. Infinity
B. Unity
C. Zero
D. Negative

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Question 16

Zero permeability/permittivity implies which state?

A. No ions are allowed in the medium
B. No current is generated in the medium
C. No magnetic or electric energy is permitted in the medium
D. No resistivity

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Question 17

The intrinsic impedance of free space is

A. 489
B. 265
C. 192
D. 377

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Question 18

In free space, the condition that holds good is

A. Minimum attenuation and propagation
B. Minimum attenuation and maximum propagation
C. Maximum attenuation and minimum propagation
D. Maximum attenuation and propagation

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Question 19

The vectors of the electromagnetic wave propagation can be expressed in

A. Dot product
B. Cross product
C. Unit vector
D. Perpendicular vector

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Question 20

The Snells law can be derived from which type of incidence?

A. Incidence angle
B. Reflected angle
C. Refracted angle
D. Oblique incidence

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Question 21

The expression for refractive index is given by

A. N = v/c
B. N = c/v
C. N = cv
D. N = 1/cv

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Question 22

Numerical aperture is expressed as the

A. NA = sin θa
B. NA = cos θa
C. NA = tan θa
D. NA = sec θa

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Question 23

For total internal reflection to occur, which condition must be satisfied?

A. N1 = N2
B. N1 > N2
C. N1 < N2
D. N1 x N2=1

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Question 24

Find the refractive index of a medium having a velocity of 1.5 x 10^8.

A. 0.5
B. 5
C. 0.2
D. 2

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Question 25

The refractive index of water will be

A. 1
B. 2.66
C. 5
D. 1.33

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Question 26

The refractive index of air is unity. State True/False.

A. True
B. False

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Question 27

The numerical aperture of a material with acceptance angle of 60 degree in water will be

A. 1.15
B. 2.15
C. 5.21
D. 1.52

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Question 28

The refractive index is 2.33 and the critical angle is 350. Find the numerical aperture.

A. 2
B. 1.9
C. 2.33
D. 12

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Question 29

Choose the optical fibre material from the given materials.

A. Glass
B. Plastic
C. Silica
D. Quartz

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Question 30

A monochromatic wave propagates along a waveguide in z direction. These points of constant phase travel in constant phase travel at a phase velocity Vp is given by?

A. Vp=ω/β
B. Vp=ω/c
C. Vp=C/N
D. Vp=mass/acceleration

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Question 31

Constructive interference occur when total phase change after two successive reflections at upper and lower interfaces is equal to? (Where m is integer)

A. 2Πm
B. Πm
C. Πm/4
D. Πm/6

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Question 32

The phenomenon which occurs when an incident wave strikes an interface at an angle greater than the critical angle with respect to the normal to the surface is called as ____________

A. Refraction
B. Partial internal reflection
C. Total internal reflection
D. Limiting case of refraction

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Question 33

What is refraction?

A. Bending of light waves
B. Reflection of light waves
C. Diffusion of light waves
D. Refraction of light waves

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Question 34

When λ is the optical wavelength in vacuum, k is given by k=2Π/λ. What does k stand for in the above equation?

A. Phase propagation constant
B. Dielectric constant
C. Boltzmann’s constant
D. Free-space constant

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Question 35

Which equations are best suited for the study of electromagnetic wave propagation?

A. Maxwell’s equations
B. Allen-Cahn equations
C. Avrami equations
D. Boltzmann’s equations

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Question 36

Which is the most important velocity in the study of transmission characteristics of optical fiber?

A. Phase velocity
B. Group velocity
C. Normalized velocity
D. Average velocity

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