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
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
Answer: (b) [MLT-3A-1]
Question 2.
The dimensional formula of is:
(a) [MLT-2A-1]
(b) [ML0T-2A-1]
(c) [ML0T-3A-1]
(d) None of these
Answer: (b) [ML0T-2A-1]
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
Answer: (c) B⃗ .dl→µ0
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→
Answer: (a) ε0E⃗ ds→
Question 5.
Maxwell’s equation involving ddt B⃗ is obtained-from:
(a) Ampere’s law
(b) Gauss’s law
(c) Faraday’s law
(d) Biot-Savart’s law
Answer: (c) Faraday’s law
Question 6.
The dimensions of E⃗ , dl→ are identical to that of:
(a) potential
(b) charge
(c) current
(d) None of these
Answer: (a) potential
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
Answer: (b) Ampere’s law
Question 8.
Choose the wave relevant to telecommunication :
(a) ultraviolet
(b) infrared
(c) microwave
(d) visible light
Answer: (c) microwave
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
Answer: (c) infrared rays
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
(d) Faraday
Answer: (a) Hertz
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
Answer: (a) c = EB
Question 16.
The dimensions of E/Bare same as that of:
(a) charge
(b) current
(c) velocity
(d) acceleration
Answer: (c) velocity
Question 17.
Name the law which states that a varying electric field produces a magnetic field:
(a) Biot-Savart’s law
(b) Faraday’s law
(c) Modified Ampere’s law
(d) None of these
Answer: (c) Modified Ampere’s law
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 :
(a) Radiowave
(b) Microwave
(c) X-ray
(d) Ultra violet
Answer: (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
Answer: (a) ue = um
Question 23.
Solar radiation is :
(a) transverse EMW
(b) longitudinal EMW
(c) both (a) and (b)
(d) None of these
Answer: (a) transverse EMW
Question 24.
Ampere’s circuital law was modified by:
(a) Laplace
(b) Gauss
(c) Maxwell
(d) Hertz
Answer: (c) Maxwell
Question 25.
Light Year is the unit of:
(a) distance
(b) time
(c) energy
(d) intensity of light
Answer: (a) distance
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