# Electromagnetic Waves MCQ Class 12 Physics

Please refer to Chapter 8 Electromagnetic Waves MCQ Class 12 Physics with answers below. These multiple-choice questions have been prepared based on the latest NCERT book for Class 12 Physics. Students should refer to MCQ Questions for Class 12 Physics with Answers to score more marks in Grade 12 Physics exams. Students should read the chapter Electromagnetic Waves and then attempt the following objective questions.

## MCQ Questions Class 12 Physics Chapter 8 Electromagnetic Waves

The Electromagnetic Waves MCQ Class 12 Physics provided below covers all important topics given in this chapter. These MCQs will help you to properly prepare for exams.

Question. In electromagnetic waves the phase difference between electric and magnetic field vectors are
(a) zero
(b) 𝜋4
(c) 𝜋2
(d) π

A

Question. Which of the following is an electromagnetic wave?
(a) α – rays
(b) β – rays
(c) γ – rays
(d) all of them

C

Question. The source of electromagnetic waves can be a charge
(a) moving with a constant velocity.
(b) moving in a circular orbit.
(c) at rest.
(d) none of these.

B

Question. If E and B represent electric and magnetic field vectors of the electromagnetic wave, the direction of propagation of electromagnetic wave is along
(a) E.
(b) B.
(c) B × E.
(d) E × B.

D

Question. A charged particle oscillates about its mean equilibrium position with a frequency of 109 Hz. The electromagnetic waves produced will not
(a) have a frequency of 109 Hz.
(b) have a frequency of 2 × 109 Hz.
(c) have a wavelength of 0.3 m.
(d) fall in the region of radio waves.

B

Question. The quantity √𝜇0𝜀0 represents
(a) speed of sound
(b) speed of light in vacuum
(c) speed of e.m. waves
(d) inverse of speed of light in vacuum

D

Question. Electromagnetic waves are transverse in nature is evident by
(a) polarisation.
(b) interference,
(c) reflection.
(d) diffraction.

A

Question. A plane electromagnetic wave propagating along x direction can have the following pairs of E and B
(a) Ex,By.
(b) Ey, Bz.
(c) Bx, Ey.
(d) None of these

B

Question. The structure of solids is investigated by using
(a) cosmic rays
(b) X-rays
(c) γ-rays
(d) infrared rays

B

Question. Electromagnetic waves with wavelength λ are used by a FM radio station for broadcasting. Here λ belongs to
(d) microwaves

B

Question. which of these electromagnetic spectrum does the wavelength 10 − 10 m correspond to?
(a)Gamma Rays
(b)X-rays
(d) Microwave

B

Question. The ultra high frequency band of radio waves in electromagnetic wave is used as in
(a) television waves
(b) cellular phone communication
(d) both (a) and (c)

B

Question. Which of the following EMW has highest wavelength?
(a) X-ray
(b) ultraviolet rays
(c) infrared rays
(d) microwaves

C

Question. A vibrating electric field creates a
(a) mechanical wave.
(b) charged particle.
(c) magnetic field.
(d) photon.

C

Question. A radio can tune to any station in the frequency range from 2.5 MHz to 15 MHz bands. What is the corresponding wavelength band?
(a) 30 m to 130 m
(b) 40 m to 140 m
(c) 20 m to 120 m
(d) 10 m to 110 m

C

Question. The ratio of contributions made by the electric field and magnetic field components to the intensity of an EM wave is
(a) c : 1
(6) c² : 1
(c) 1 : 1
(d) √c : 1

C

Question. 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

D

Question. Which of the following electromagnetic rays has maximum wavelength
(a) UV rays
(b) Infrared rays
(c) X -rays

D

Question. 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

C

Question. The quantity √𝜇0𝜀0 represents
(a) speed of sound
(b) speed of light in vacuum
(c) speed of e.m. waves
(d) inverse of speed of light in vacuum

D

Question. An electromagnetic wave consists of a vibrating
(a) magnetic field.
(b) electric field.
(c) particle of matter.
(d) two of the above

D

Question. The conduction current is same as displacement current when source is
(a) ac only
(b) dc only
(c) either ac or dc
(d) neither dc nor ac

C

Question. Displacement current is due to:
(a) the flow of electrons
(b) the Varying electric field
(c) the ionization of atmosphere
(d) the flow of protons

B

Question. 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.

A

Question. Choose the wave relevant to telecommunication :
(a) ultraviolet
(b) infrared
(c) microwave
(d) visible light

C

Question. Light with an energy flux of 20 W/cm2 falls on a non-reflecting surface at normal incidence. If the surface has an area of 30 cm2. the total momentum delivered (for complete absorption) during 30 minutes is
(a) 36 × 10–5 kg m/s.
(b) 36 × 10–4 kg m/s.
(c) 108 × 104 kg m/s.
(d) 1.08 × 107 kg m/s.

B

Question. Which of the following laws was modified by Maxwell by introducing the displacement current?
(a) Gauss’s law
(b) Ampere’s law
(c) Biot-Savart’s law
(d) None of these

B

Question. Electromagnetic waves may vary in their
(a) speed across space.
(b) energy level.
(c) frequency.
(d) two of the above

D

Question. What frequency are 20 mm microwaves?
(a) 100 MHz
(b) 400 MHz|
(c) 15 GHz
(d) 73 GHz

C

Question. Which of the following electromagnetic radiation is used for viewing objects through fog
(a) microwave
(b) gamma rays
(c) X- rays
(d) infrared

D

Question. What is the full form of UHF?
(a) Under heavy frequency
(b) Ultra-high frequency
(c) Ultra heavy frequency
(d) Under high frequency

B

Question. Which of the following has/have zero average value in a plane electromagnetic wave?
(a) Both magnetic and electric fields
(b) Electric field only
(c) Magnetic field only
(d) None of these

A

Question. Which of the following can be used to produce a propagating electromagnetic wave?
(a) Charge moving at a constant speed
(b) Chargeless particle
(c) Stationary charge
(d) An accelerating charge

D

Question. Which among the following is an application of microwaves?
(a) Solar cells
(b) Ovens
(d) Burglar alarms

B

Question. If the frequency of an electromagnetic wave is 3.0 X 10^8 hertz, what is its wavelength?
(a) 1 mm
(b) 1 cm
(c) 1 m
(d) 1 km

C

Question. Which of the following rays are not electromagnetic waves?
(a) Gamma rays
(b) Beta rays
(c) Heat rays
(d) X rays

B

Question. Which of the following is NOT true for electromagnetic waves?.
(a) it transport energy
(b) it transport momentum
(c) it transport angular momentum
(d) in vacuum, it travels with different speeds which depend on their frequency

D

Question. Which of the following has maximum penetrating power?
(b) Microwaves
(c) γ-rays

C

Question. Electromagnetic waves are produced by
(a) A static charge
(b) An accelerated charge
(c) A moving charge
(d) Charged particles

B

Question. Properties of electromagnetic waves include
(a) speed.
(b) wavelength.
(c) frequency.
(d) all of the above

D

Question. Which of the following has/have zero average value in a plane electromagnetic wave ?
(a) Both magnetic and electric field
(b) Electric field only
(c) Magnetic energy
(d) Electric energy

A

Question. Which of the following shows green house effect ?
(a) Ultraviolet rays
(b) Infrared rays
(c) X-rays
(d) None of these

B

Question. The ratio of electric field vector E and magnetic field vector H i.e., (E/H) has the dimensions of
(a) resistance
(b) inductance
(c) capacitance
(d) product of inductance and capacitance

A

Question. To double the covering range of a T.V. transmitter tower, its height should be made
(a) 2 times
(b) 4 times
(c) 2 times
(d) 8 times

B

Question. For sky wave propagation of a 10 MHz signal, what should be the maximum electron density in ionosphere?
(a) ~1.2 × 1012m–3
(b) ~106m–3
(c) ~1014 m–3
(d) ~1022m–3

A

Question. A plane electromagnetic wave is incident on a plane surface of area A, normally and is perfectly reflected. If energy E strikes the surface in time t then average pressure exerted on the surface is (c = speed of light)
(a) zero
(b) E/Atc
(c) 2E/Atc
(d) E/c

C

Question. Maxwell in his famous equation of electromagnetism introduced the concept of
(a) a.c. current
(b) d.c. current
(c) displacement current
(d) impedance

C

Question. The transmitting antenna of a radiostation is mounted vertically. At a point 10 km due north of the transmitter the peak electric field is 10–3 Vm–1. The magnitude of the radiated magnetic field is
(a) 3.33 × 10–10 T
(b) 3.33 × 10–12 T
(c) 10–3 T
(d) 3 × 105 T

B

Question. The oscillating electric and magnetic vectors of an electromagnetic wave are oriented along
(a) the same direction but differ in phase by 90°
(b) the same direction and are in phase
(c) mutually perpendicular directions and are in phase
(d) mutually perpendicular directions and differ in phase by 90°

C

Question. The wave impendance of free space is
(a) zero
(b) 376.6 W
(c) 33.66W
(d) 3.76 W