Electromagnetic Waves  MCQs

MCQs of Electromagnetic Waves

Showing 1 to 10 out of 112 Questions
1.
Astronomers have found that the electromagnetic waves of wavelength 21 cm are continuously reaching the Earth's surface. The frequency of this radiation is _____ . (c = 3 × 108 ms-1 )
(a) 1.43 GHz
(b) 1.43 MHz
(c) 1.43 kHz
(d) 1.43 Hz
Answer:

Option (a)

2.
In Hertz's experiment the _____ of the electromagnetic waves is equal to the kinetic energy of the charges oscillating between the two spheres.
(a) frequency
(b) energy
(c) wavelength
(d) velocity
Answer:

Option (b)

3.
The electromagnetic waves in the range of wavelengths from 3 mm to 100 cm are used for the purpose of satellite communication. The range of frequencies corresponding to this range of wavelengths is _____ .(c = 3 × 108 ms-1 )
(a) 30 MHz to 104
MHz
(b) 300 MHz to 105
MHz
(c) 3 MHz to 3 × 108
MHz
(d) 3 MHz to 106
MHz
Answer:

Option (b)

4.
If vg, vx and vm are the velocities of the γ-rays, X- rays and microwaves respectively in space, then
(a) vg > vx > vm
(b) vg < vx < vm
(c) vx > vm > vg
(d) vg = vx = vm
Answer:

Option (d)

5.
If μr be relative permeability and K be dielectric constant of a given medium, then the refractive index of the medium is n = _____ .
(a) μrK 
(b)  μ0ε0
(c) 1μrk 
(d) μrK
Answer:

Option (a)

6.
The maximum value of E in an electromagnetic wave is equal to 18 Vm-1. Thus the maximum value of B is _____ . 
(a) 3 × 10-6 T
(b) 6 × 10-8 T
(c) 9 × 10-9 T
(d) 2 ×10-10 T
Answer:

Option (b)

7.
An electromagnetic wave passing through the space is given by equations : E =E0sin(ωt - kx) and B = B0sin(ωt - kx). Which of the following is true ?
(a) E0B0= ωk
(b) E0ω = B0k
(c) E0k = B0ω
(d) E0B0 = 1ωk
Answer:

Option (c)

8.
A plane electromagnetic wave is travelling along the X-direction. The electric field vector at an arbitrary point at a time is E = 6.3 j^ Vm-1. The magnetic field at that point at that time is _____ .
(a) 2.1 × 10-8 K^ T
(b) -2.1 × 10-8 K^ T
(c) 6.3 K^ T
(d) -6.3 K^ T
Answer:

Option (a)

9.
Two opposite charged particles oscillate about their mean equilibrium position in free space, with a frequency of 109 Hz. The wavelength of the corresponding electromagnetic wave produced is _____ .
(a) 0.3 m
(b) 3 × 1017 m
(c) 109 m
(d) 3.3 m
Answer:

Option (a)

10.
The wavelengths 5890 Å and 5896 Å of sodium doublet correspond to ________ region the electromagnetic spectrum.
(a) infrared
(b) visible light
(c) ultraviolet
(d) microwave
Answer:

Option (b)

Showing 1 to 10 out of 112 Questions