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EC8451 EMF - UNIT - V (PLANE ELECTROMAGNETIC WAVES)

Total questions: 30

Worksheet time: 30mins

Name
Class
Date
1.

If the amplitude of the magnetic field is 3 × 10−6 T, then amplitude of the electric field for a electromagnetic waves is

a)

100 V m−1

b)

300 V m−1

c)

600 V m−1

d)

900 V m−1

2.

Which of the following electromagnetic radiation is used for viewing objects through fog

a)

microwave

b)

gamma rays

c)

X- rays

d)

infrared

3.

Which of the following are false for electromagnetic waves

a)

transverse

b)

mechanical waves

c)

longitudinal

d)

produced by accelerating charges

4.

Consider an oscillator which has a charged particle and oscillates about its mean position with a frequency of 300 MHz. The wavelength of electromagnetic waves produced by this oscillator is

a)

1 m

b)

10 m

c)

100 m

d)

1000 m

5.

Electromagnetic waves do not transport

a)

energy

b)

charge

c)

momentum

d)

information

6.

Electromagnetic waves ware transverse in nature is evident by

a)

polarization

b)

interference

c)

reflection

d)

diffraction

7.

Speed of electromagnetic waves is same

a)

for all wavelengths

b)

in all media

c)

for all intensities

d)

for all frequencies

8.

According to depth of penetration, what is the percentage proportion of attenuated wave w.r.t its original value?

a)

17%

b)

27%

c)

37%

d)

57%

9.

In an electrical circuit,which nature of impedance causes the current & voltages in phase?

a)

Reactive

b)

Resistive

c)

Capacitive

d)

Inductive

10.

If the magnetic field component of a plane wave in a lossless dielectric is H = 50 sin (2π x 106 t – 6x) az mA/m , what will be the wave velocity?

a)

1.047 x 106 m/s

b)

1.257 x 106 m/s

c)

2.50 x 106 m/s

d)

3 x 106 m/s

11.

Which equations are regarded as wave equations in frequency domain for lossless media?

a)

Maxwell's

b)

Lorentz

c)

Helmholtz

d)

Poisson's

12.

Which among the following exhibits perpendicular nature in TEM wave?

a)

Electric field

b)

Magnetic field

c)

Direction of propagation

d)

All of the above

13.

In which kind of waveform is the phase velocity defined?

a)

Sinusoidal

b)

Rectangular

c)

Square

d)

Triangular

14.

During the propagation of electromagnetic waves in a medium

a)

electric energy density is double of the magnetic energy density

b)

electric energy density is half of the magnetic energy density

c)

electric energy density is equal to the magnetic energy density

d)

both electric and magnetic energy densities are zero

15.

Electromagnetic waves are produced by

a)

accelerated charged particle

b)

deaccelerated charged particle

c)

charge in uniform motion

d)

none of the above

16.

All electromagnetic waves travel through a vacuum at

a)

the same speed.

b)

speeds that are proportional to their frequency.

c)

speeds that are inversely proportional to their frequency.

d)

None of the above.

17.

The E and B fields in electromagnetic waves are oriented

a)

parallel to the wave's direction of travel, as well as to each other.

b)

parallel to the waves direction of travel, and perpendicular to each other.

c)

perpendicular to the wave's direction of travel, and parallel to each other.

d)

perpendicular to the wave's direction of travel, and also to each other.

18.

An electromagnetic wave is radiated by a straight wire antenna that is oriented vertically. What should be the orientation of a straight wire receiving antenna? It should be placed

a)

vertically.

b)

horizontally and in a direction parallel to the wave's direction of motion.

c)

horizontally and in a direction perpendicular to the wave's direction of motion.

d)

None of the above.

19.

An electromagnetic wave is traveling to the east. At one instant at a given point its E vector points straight up. What is the direction of its B vector?

a)

north

b)

down

c)

east

d)

south

20.

Which of the following correctly lists electromagnetic waves in order from longest to shortest wavelength?

a)

gamma rays, ultraviolet, infrared, microwaves

b)

microwaves, ultraviolet, visible light, gamma rays

c)

radio waves, infrared, gamma rays, ultraviolet

d)

television, infrared, visible light, X-rays

21.

What is the wavelength of light waves if their frequency is 5.0X1014 Hz?

a)

0.60 m

b)

6.0 mm

c)

0.060 mm

d)

0.60 micro-m

22.

How long does it take light to travel 1.0 m?

a)

3.3 ns

b)

3.3 micro-s

c)

3.3 ms

d)

3.3 s

23.

What is the wavelength of a 92.9 MHz radio wave?

a)

32 mm

b)

32 cm

c)

3.2 m

d)

32 m

24.

What frequency are 20 mm microwaves?

a)

100 MHz

b)

400 MHz

c)

15 GHz

d)

73 GHz

25.

Electromagnetic waves that include light belong to

a)

light spectrum

b)

electronic spectrum

c)

electromagnet group

d)

electromagnetic spectrum

26.

For an electromagnetic wave incident from one medium to a second medium, total reflection takes place when

a)

The angle of incidence is equal to the Brewster angle with E field perpendicular to the plane of incidence.

b)

The angle of incidence is equal to the Brewster angle with E field parallel to the plane of incidence

c)

The angle of incidence is equal to the critical angle with the wave moving from the denser medium to a rarer medium

d)

The angle of incidence is equal to the critical angle with the wave moving from a rarer medium to a denser medium

27.

A uniform plane wave in air is normally incident on an infinitely thick slab. If the refractive index of glass slab is 1.5, then the percentage of the incident power that is reflected from the air – glass interface is

a)

0%

b)

4%

c)

20%

d)

100%

28.

Some unknown material has a conductivity of 106 mho/m and a permeability of 4𝜋×10−7 𝐻/𝑚. The skin depth for the material at 1 GHz

a)

15.9 𝜇m

b)

20.9 𝜇m

c)

25.9 𝜇m

d)

30.9 𝜇m

29.

A plane electromagnetic wave propagating in free space is incident normally on a large slab of loss – less, non – magnetic, dielectric material with 𝜀 > 𝜀0. Maxima and minima are observed when the electric field is measured in front of the slab. The maximum electric field is found to be 5 times the minimum field. The intrinsic impedance of the medium should

a)

120 𝜋 Ω

b)

60 𝜋 Ω

c)

600 𝜋 Ω

d)

24 𝜋 Ω

30.

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

a)

8/9

b)

1/2

c)

1/3

d)

5/6