A plane EM wave travels in free space along X-axis. At a particular point in space, the electric field along Y-axis is 9.3 Vm -1. The magnetic induction is
1) 3.1 × 10-8 T 2) 3 × 10-5 T 3) 3 × 10-6 T 4) 9.3 × 10-6 T... View Article
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The sun delivers 103 Wm-2 of electromagnetic flux on the earth’s surface. The total power that is incident on a roof of dimensions 6 m × 30 m, is
1) 1.8 × 105 W 2) 7.2 × 105 W 3) 0.9 × 105 W 4) 4.5 × 105 W... View Article
The refractive index and the permeability of a medium are 1.5 Hm– 1 and 5 × 10-7 Hm -1 respectively. The relative permittivity of the medium is nearly
1) 25 2) 15 3) 81 4) 10 5) 6 Answer: 5) 6 Solution: The refractive index of the medium is... View Article
If 150 J of energy is incident on area 2 m2. If Qr =15 J, coefficient of absorption is 0.6, then the amount of energy transmitted is
1) 50 J 2) 45 J 3) 40 J 4) 30 J Answer: 2) 45 J Solution: When the thermal radiation... View Article
If a source is transmitting electromagnetic waves of frequency 8.196 × 106 Hz, then the wavelength of the electromagnetic waves transmitted from the source will be
1) 5090 cm 2) 4050 cm 3) 4230 cm 4) 3660 cm Answer: 4) 3660 cm Solution: Given, Frequency of the electromagnetic... View Article
A charged particle oscillates about its mean equilibrium position with a frequency of 109 Hz. The frequency of the electromagnetic wave produced by the oscillator is
1) 10 Hz 2) 105 Hz 3) 109 Hz 4) 1010 Hz Answer: 3) 109 Hz Solution: The frequency of the electromagnetic... View Article
The amplitude of the magnetic field part of a harmonic electromagnetic wave in a vacuum is B0 = 510 nT. What is the amplitude of the electric field part of the wave?
1) 140 NC-1 2) 153 NC-1 3) 163 NC-1 4) 133 NC-1 Answer: 2) 153 NC-1 Solution: The magnitude of the... View Article
Radio waves of constant amplitude can be generated with
1) rectifier 2) filter 3) F.E.T 4) Oscillator Answer:4) Oscillator Solution: Radio waves are a type of electromagnetic radiation. The... View Article
In an electromagnetic wave, the average energy density associated with the magnetic field is
1) Li02/2 2) B2/2μ0 3) μ0B2/2 4) μ0/2B2 Answer: 2) B2/2μ0 Solution: The energy density due to electric field = (1/2)ε0E2 ——–(1) Now, E... View Article
The voltage applied across an X-rays tube is nearly equal to
1) 10 V 2) 100 V 3) 1000 V 4) 10,000 V. Answer: 4) 10,000 V. Solution: V = hc/eλ =... View Article
The wavelength of x-rays is of the order of
1) 1 metre 2) 1 cm 3) 1 micron 4) 1 angstrom Answer: 4) 1 angstrom Solution: The wavelength of x-rays... View Article
The equation out of four Maxwell’s equations which show electric field lines do not form closed loops
(i) \(\begin{array}{l}\oint \vec{E}.\vec{ds}=\frac{q_{0}}{\varepsilon _{0}}\end{array} \) (ii) \(\begin{array}{l}\oint \vec{B}.\vec{ds}= 0\end{array} \) (iii) \(\begin{array}{l}\oint \vec{E}.\vec{dl}=\frac{d}{dt}\oint \vec{B}.\vec{ds}\end{array} \) (iv) \(\begin{array}{l}\oint \vec{B}.\vec{ds}=\mu _{0}\varepsilon _{0}\frac{d}{dt}\oint... View Article
Electromagnetic radiation has an energy of 13.2 keV. Then, the radiation belongs to the region of
1) visible light 2) ultraviolet 3) infrared 4) X – rays Answer: 4) X – rays Solution: Energy = 13.2 keV... View Article
In an electromagnetic wave, the direction of propagation is in the direction of
1) E 2) B 3) E × B 4) None of these Answer: 3) E × B Solution: The direction of... View Article
Electromagnetic waves can be deflected by
1) electric field only 2) magnetic field only 3) Both (1) and (2) 4) None of the above Answer: 4)... View Article
An electromagnetic wave of frequency v = 3.0 MHz passes from vacuum into a dielectric medium with permittivity ε = 4.0. Then
1) wavelength is doubled and the frequency remains unchanged 2) wavelength is doubled and frequency becomes half 3) wavelength is... View Article
The dielectric constant of air is 1.006. The speed of electromagnetic waves travelling in air is a × 108 ms-1, where, a is about
1) 3 2) 3.88 3) 2.5 4) 3.2 5) 2.8 Answer: 1) 3 Solution: Speed of electromagnetic wave, c = 1/√µ0ε0... View Article
A point source of electromagnetic radiation has an average power output of 1500 W. The maximum value of the electric field at a distance of 3 m from this source in Vm -1 is
1) 500 2) 100 3) 500/3 4) 250/3 5) 10√5 Answer: 2) 100 Solution: Average Intensity of an electromagnetic wave is... View Article
An electromagnetic wave has
1) electric vector only 2) magnetic vector only 3) electric and magnetic vectors perpendicular to each other 4) Neither the... View Article
The speed of electromagnetic waves in a vacuum depends upon the source of radiation. It
1) increases as we move from γ-rays to radio waves 2) decreases as we move from γ-rays to radio waves... View Article
