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Free download in PDF Class 12 Physics Chapter 8 Electromagnetic Waves Current Induction Multiple Choice Questions and Answers for Board, JEE, NEET, AIIMS, JIPMER, IIT-JEE, AIEE and other competitive exams. MCQ Questions for Class 12 Physics with Answers were prepared based on the latest exam pattern. These short solved questions or quizzes are provided by Gkseries. These will help the students for preparation of their examination./p>
(1)
The waves used by artificial satellites for communication is
[A]
microwaves
[B]
infrared waves
[C]
radio waves
[D]
X-rays
(2)
A charged particle oscillates about its mean equilibrium position with a frequency of 109 Hz. The frequency of electromagnetic waves produced by the oscillator is
[A]
106 Hz
[B]
107 Hz
[C]
108 Hz
[D]
109 Hz
(3)
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
Answer: Both magnetic and electric fields
(4)
Which of the following statement is false for the properties of electromagnetic waves?
[A]
Both electric and magnetic field vectors attain the maxima and minima at the same place and same time.
[B]
The energy in electromagnetic waves is divided equally between electric and magnetic field vectors
[C]
Both electric and magnetic field vectors are parallel to each other and perpendicular to the direction of propagation of wave.
[D]
These waves do not require any material medium for propagation.
Answer: Both electric and magnetic field vectors are parallel to each other and perpendicular to the direction of propagation of wave.
(5)
If a variable frequency ac source is connected to a capacitor then with decrease in frequency the displacement current will
[A]
increase
[B]
decrease
[C]
remains constant
[D]
first decrease then increase
(6)
Maxwell in his famous equations of electromagnetism introduced the concept of
[A]
ac current
[B]
displacement current
[C]
impedance
[D]
reactance
Answer: displacement current
(7)
The ultra high frequency band of radio waves in electromagnetic wave is used as in
[A]
television waves
[B]
cellular phone communication
[C]
commercial FM radio
[D]
both (a) and (c)
Answer: cellular phone communication
(8)
An electromagnetic wave can be produced, when charge is
[A]
moving with a constant velocity
[B]
moving in a circular orbit
[C]
falling in an electric field
[D]
both (b) and (c)
(9)
Which of the following electromagnetic waves is used in medicine to destroy cancer cells?
[A]
IR-rays
[B]
Visible rays
[C]
Gamma rays
[D]
Ultraviolet rays
(10)
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
(11)
Ampere’s circuital law was modified by:
[A]
Laplace
[B]
Gauss
[C]
Maxwell
[D]
Hertz
(12)
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: Electromagnetic waves travel with the same speed in all media
(13)
The existence of EMW was experimentally established by :
[A]
Sir S. C. Bose
[B]
Maxwell
[C]
Marconi
[D]
Hertz
(14)
The dimensions of E/Bare same as that of:
[A]
charge
[B]
current
[C]
velocity
[D]
acceleration
(15)
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: accelerated or decelerated charge only
(16)
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: the Varying electric field
(17)
Choose the wave relevant to telecommunication :
[A]
ultraviolet
[B]
infrared
[C]
microwave
[D]
visible light
(18)
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: equal to conduction current
(19)
Which of the following EMW has highest wavelength?
[A]
X-ray
[B]
ultraviolet rays
[C]
infrared rays
[D]
microwaves
(20)
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 theseL
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