    # MCQ Questions for Class 12 Physics Chapter 8 Electromagnetic Waves with answer

MCQ Questions for Class 12 Physics Chapter 8 Download Free PDF: CBSE RBSE and NCERT Physics class 12 MCQs for Chapter 8 “Electromagnetic Waves” is very important for the students who want to get good marks. Neet MCQs

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## MCQ Questions for Class 12 Physics Chapter 8 Electromagnetic Waves with PDF

Question 1.
The dimensional formula of E⃗  is:
(a)[MLT-2A-1]
(b) [MLT-3A-1]
(c) [MLT-2A-2]
(d) None of these

Question 2.
The dimensional formula of is:
(a) [MLT-2A-1]
(b) [ML0T-2A-1]
(c) [ML0T-3A-1]
(d) None of these

Question 3.
Which of the following has the dimensions of current?
(a) ε0 E⃗ .dt→
(b) µ0 E⃗ .dt→
(c) B⃗ .dl→µ0
(d) B⃗ .dl→ε0

Question 4.
Which of the following has the dimensions of charge?
(a) ε0E⃗ ds→
(b) µ0 E⃗ .ds→
(c) ε0µ0 E⃗ .ds→
(d) µ0ε0 E⃗ .ds→

Question 5.
Maxwell’s equation involving ddt B⃗  is obtained-from:
(a) Ampere’s law
(b) Gauss’s law
(d) Biot-Savart’s law

Question 6.
The dimensions of E⃗ , dl→ are identical to that of:
(a) potential
(b) charge
(c) current
(d) None of these

Question 7.
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

Question 8.
Choose the wave relevant to telecommunication :
(a) ultraviolet
(b) infrared
(c) microwave
(d) visible light

Question 9.
Electromagnetic waves have a speed of
(a) 3 × 105 kms-1
(b)3 × 106 kms-1
(c) 3 × 107 kms-1
(d) 3 × 108 kms-1

Answer: (a) 3 × 105 kms-1

Question 10.
Which of the following EMW has highest wavelength?
(a) X-ray
(b) ultraviolet rays
(c) infrared rays
(d) microwaves

Question 11.
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

Answer: (b) the Varying electric field

Question 12.
Displacement current is always :
(a) equal to conduction current
(b) less than conduction current
(c) greater than conduction current
(d) the sum of current due to flow of positive and negative ions

Answer: (a) equal to conduction current

Question 13.
EMW are produced by:
(a) charge in uniform motion only
(b) charge at rest only
(c) accelerated or decelerated charge only
(d) all of the above

Answer: (c) accelerated or decelerated charge only

Question 14.
Who first demonstrated the existence of em waves?
(a) Hertz
(b) Maxwell
(c) Ampere

Question 15.
If B⃗  is the magnetic field vector and E⃗  is the electric field vector in an em wave, then which of the following relations is correct? Here c is the speed of fight:
(a) c = EB
(b) c = BE
(c) c = BE
(d) c = 1EB

Question 16.
The dimensions of E/Bare same as that of:
(a) charge
(b) current
(c) velocity
(d) acceleration

Question 17.
Name the law which states that a varying electric field produces a magnetic field:
(a) Biot-Savart’s law
(c) Modified Ampere’s law
(d) None of these

Question 18.
The existence of EMW was experimentally established by :
(a) Sir S. C. Bose
(b) Maxwell
(c) Marconi
(d) Hertz

Answer: (a) Sir S. C. Bose

Question 19.
An EMW of v = 3 MHz passes from vacuum into dielectric medium with permittivity Er = 4, then:
(a) Wavelength is doubled and the frequency remains unchanged
(b) Wavelength is doubled and the frequency become half
(c) Wavelength is halved and the frequency remains unchanged
(d) Wavelength and frequency both remain unchanged

Answer: (c) Wavelength is halved and the frequency remains unchanged

Question 20.
Frequency of a wave is 6 × 1015. Hz. The wave is :
(b) Microwave
(c) X-ray
(d) Ultra violet

Question 21.
Choose the wrong statement?
(a) Electromagnetic waves are transverse
(b) Electromagnetic waves travel with the speed of light in free space
(c) Electromagnetic waves are produced by accelerating charges
(d) Electromagnetic waves travel with the same speed in all media

Answer: (d) Electromagnetic waves travel with the same speed in all media

Question 22.
If ue and um arc the electric and magnetic field densities in an electromagnetic wave, then (c is the speed of light):
(a) ue = um
(b) ue = c um
(c) ue = umc
(d) None of these

Question 23.
(a) transverse EMW
(b) longitudinal EMW
(c) both (a) and (b)
(d) None of these

Question 24.
Ampere’s circuital law was modified by:
(a) Laplace
(b) Gauss
(c) Maxwell
(d) Hertz

Question 25.
Light Year is the unit of:
(a) distance
(b) time
(c) energy
(d) intensity of light