Q1
Allen
1. Conceptual Questions
MCQ
If $\vec{E}$ and $\vec{B}$ are the electric and magnetic field vectors of electromagnetic waves then the direction of propagation of electromagnetic wave is along the direction of -
A.
$\vec{E}$
B.
$\vec{B}$
C.
$\vec{E} \times \vec{B}$
D.
none of these
Q2
Allen
1. Conceptual Questions
MCQ
The electromagnetic waves do not transport -
A.
energy
B.
charge
C.
momentum
D.
information
Q3
Allen
1. Conceptual Questions
MCQ
The wave function (in S.I. units) for an electromagnetic wave is given as - $\psi (\mathrm{x},\mathrm{t}) = 10^{3}\sin \pi (3\times 10^{6}\mathrm{x} - 9\times 10^{14}\mathrm{t})$ The speed of the wave is -
A.
$9\times 10^{14}\mathrm{m / s}$
B.
$3\times 10^{8}\mathrm{m / s}$
C.
$3\times 10^{6}\mathrm{m / s}$
D.
$3\times 10^{7}\mathrm{m / s}$
Q4
Allen
1. Conceptual Questions
MCQ
In the above problem, wavelength of the wave is -
A.
$666\mathrm{nm}$
B.
$666 Å$
C.
$666\mu \mathrm{m}$
D.
$6.66\mathrm{nm}$
Q5
Allen
1. Conceptual Questions
MCQ
In an electromagnetic wave the average energy density is associated with -
A.
electric field only
B.
magnetic field only
C.
equally with electric and magnetic fields
D.
average energy density is zero
Q6
Allen
1. Conceptual Questions
MCQ
In an electromagnetic wave the energy density associated with magnetic field will be
A.
$\frac{1}{2}Ll^{2}$
B.
$\frac{B^{2}}{2\mu_{0}}$
C.
$\frac{1}{2}\mu_{0}B^{2}$
D.
$\frac{1}{2}\frac{\mu_{0}}{B^{2}}$
Q7
Allen
1. Conceptual Questions
MCQ
In the above problem, the energy density associated with the electric field will be -
A.
$\frac{1}{2}CV^{2}$
B.
$\frac{1}{2}\frac{q^{2}}{C}$
C.
$\frac{1}{2}\frac{\varepsilon^{2}}{E}$
D.
$\frac{1}{2}\varepsilon_{0}E^{2}$
Q8
Allen
1. Conceptual Questions
MCQ
If there were no atmosphere, the average temperature on earth surface would be -
A.
lower
B.
higher
C.
same
D.
0°C
Q9
Allen
1. Conceptual Questions
MCQ
In which part of earth's atmosphere is the ozone layer present?
A.
troposphere
B.
stratosphere
C.
ionosphere
D.
mesosphere
Q10
Allen
1. Conceptual Questions
MCQ
The ozone layer is earth's atmosphere is crucial for human survival because it –
A.
contains ions
B.
reflects radio signals
C.
reflects ultraviolet rays
D.
reflects infrared rays
Q11
Allen
1. Conceptual Questions
MCQ
The frequency from $3 \times 10^{9}$ Hz to $3 \times 10^{10}$ Hz is –
A.
high frequency band
B.
super high frequency band
C.
ultra high frequency band
D.
very high frequency band
Q12
Allen
1. Conceptual Questions
MCQ
The frequency from 3MHz to 30 MHz is known as -
A.
audio band
B.
medium frequency band
C.
very high frequency band
D.
high frequency band
Q13
Allen
1. Conceptual Questions
MCQ
The AM range of radiowaves have frequency –
A.
less than 30 MHz
B.
more than 30 MHz
C.
less than 20000Hz
D.
more than 20000Hz
Q14
Allen
1. Conceptual Questions
MCQ
Select wrong statement from the following for EMW-
A.
are transverse
B.
travel with same speed in all medium
C.
travel with the speed of light
D.
are produced by accelerating charge
Q15
Allen
1. Conceptual Questions
MCQ
The waves related to tele-communication are -
A.
infrared
B.
visible light
C.
microwaves
D.
ultraviolet rays
Q16
Allen
1. Conceptual Questions
MCQ
The nature of electromagnetic wave is –
A.
longitudinal
B.
longitudinal stationary
C.
transverse
D.
transverse stationary
Q17
Allen
1. Conceptual Questions
MCQ
Greenhouse effect keeps the earth surface –
A.
cold at night
B.
dusty and cold
C.
warm at night
D.
moist
Q18
Allen
1. Conceptual Questions
MCQ
The speed of electromagnetic radiation in vacuum is:-
A.
$\mu_{0}\varepsilon_{0}$
B.
$\sqrt{\mu_{0}\varepsilon_{0}}$
C.
$\frac{1}{\mu_{0}\varepsilon_{0}}$
D.
$\frac{1}{\sqrt{\mu_{0}\varepsilon_{0}}}$
Q19
Allen
1. Conceptual Questions
MCQ
What is the cause of greenhouse effect?
A.
Infrared rays
B.
Ultraviolet rays
C.
X-rays
D.
Radio waves
Q20
Allen
1. Conceptual Questions
MCQ
The conduction current is the same as displacement current when source is :-
A.
ac only
B.
dc only
C.
both ac and dc
D.
neither dc nor ac
Q21
Allen
2. PYQ
MCQ
The energy of the em waves is of the order of 15 keV. To which part of the spectrum does it belong?
A.
γ-rays
B.
X-rays
C.
Infra-red rays
D.
Ultraviolet rays
Q22
Allen
2. PYQ
MCQ
A radiation of energy 'E' falls normally on a perfectly reflecting surface. The momentum transferred to the surface is (c = Speed of light) :-
A.
$\frac{2E}{c}$
B.
$\frac{2E}{c^{2}}$
C.
$\frac{E}{c^{2}}$
D.
$\frac{E}{c}$
Q23
Allen
2. PYQ
MCQ
Out of the following options which one can be used to produce a propagating electromagnetic wave?
A.
A charge moving at constant velocity
B.
A stationary charge
C.
A chargeless particle
D.
An accelerating charge
Q24
Allen
2. PYQ
MCQ
A 100 Ω resistance and a capacitor of 100 Ω reactance are connected in series across a 220 V source. When the capacitor is 50% charged, the peak value of the displacement current is :-
A.
4.4 A
B.
$11\sqrt{2}$ A
C.
2.2 A
D.
11 A
Q25
Allen
2. PYQ
MCQ
In an electromagnetic wave in free space the root mean square value of the electric field is $E_{rms} = 6V/m$ . The peak value of the magnetic field is :-
A.
$2.83 \times 10^{-8}$ T
B.
$0.70 \times 10^{-8}$ T
C.
$4.23 \times 10^{-8}$ T
D.
$1.41 \times 10^{-8}$ T