MCQs of Electromagnetic Waves

Electromagnetic Waves MCQs

MCQs of Electromagnetic Waves

Showing 1 to 10 out of 112 Questions

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

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

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

If v_g, v_x and v_m are the velocities of the γ-rays, X- rays and microwaves respectively in space, then

(a)	v_g > v_x > v_m
(b)	v_g < v_x < v_m
(c)	v_x > v_m > v_g
(d)	v_g = v_x = v_m

μ_{r}

be relative permeability and K be dielectric constant of a given medium, then the refractive index of the medium is n = _____ .

(a)	$\sqrt{μ_{r} K}$
(b)	$\sqrt{μ_{0} ε_{0}}$
(c)	$\frac{1}{μ_{r} k}$
(d)	$\sqrt{\frac{μ_{r}}{K}}$

The maximum value of \vec{E} in an electromagnetic wave is equal to 18 {Vm}^{- 1} . Thus the maximum value of \vec{B} is_____.

(a)	3 × 10^-6 T
(b)	6 × 10^-8 T
(c)	9 × 10^-9 T
(d)	2 ×10^-10 T

An electromagnetic wave passing through the space is given by equations : E = E_{0} \sin (ωt - k x) and B = B_{0} \sin (ωt - kx) . Which of the following is true ?

(a)	$E_{0} B_{0} = ω k$
(b)	$E_{0} ω = B_{0} k$
(c)	$E_{0} k = B_{0} ω$
(d)	$\frac{E_{0}}{B_{0}} = \frac{1}{ω k}$

A plane electromagnetic wave is travelling along the X - direction . The electric field vector at an arbitrary point at a time is \vec{E} = 6.3 \hat{j} {Vm}^{- 1} . The magnetic field at that point at that time is_____.

(a)	$2.1 \times 10^{- 8} \hat{K} T$
(b)	$- 2.1 \times 10^{- 8} \hat{K} T$
(c)	$6.3 \hat{K} T$
(d)	$- 6.3 \hat{K} T$

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

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

Showing 1 to 10 out of 112 Questions