Characteristics of Electromagnetic Waves

Interactive Feed

LEVELJEE Main

In an X-ray tube, electrons accelerated through a potential difference of 15, 000 V strike a copper target. The speed of the emitted X-ray inside the tube is ....... m/s.

LEVELJEE Main

If $ε_{0}$ and $μ_{0}$ are, respectively, the electric permittivity and magnetic permeability of free space, $ε$ and $μ$ the corresponding quantities in a medium, the index of refraction of the medium in terms of the above parameters is .........

JEE Advanced 2021

LEVELJEE Main

A physical quantity $S$ is defined as $S = (E \times B) / μ_{0}$ , where $E$ is electric field, $B$ is magnetic field and $μ_{0}$ is the permeability of free space. The dimensions of $S$ are the same as the dimensions of which of the following quantity (ies) ?

* Multiple Correct Options

(A)

\frac{Energy}{charge \times current}

(B)

\frac{Force}{Length \times Time}

(C)

\frac{Energy}{Volume}

(D)

\frac{Power}{Area}

JEE Advanced 2023

LEVELJEE Advanced

The electric field associated with an electromagnetic wave propagating in a dielectric medium is given by $E = 30 (2 \overset{x}{^} + \overset{y}{^}) sin [2 π (5 \times 1 0^{14} t - \frac{1 0 ^{7}}{3} z)] V m^{- 1}$ . Which of the following option(s) is(are) correct? [Given: The speed of light in vacuum, $c = 3 \times 1 0^{8} ms^{- 1}$ ]

* Multiple Correct Options

(A)

B_{x} = - 2 \times 1 0^{- 7} sin [2 π (5 \times 1 0^{14} t - \frac{1 0 ^{7}}{3} z)] Wbm^{- 2}

(B)

B_{y} = 2 \times 1 0^{- 7} sin [2 π (5 \times 1 0^{14} t - \frac{1 0 ^{7}}{3} z)] Wbm^{- 2}

(C)

The wave is polarized in the xy-plane with polarization angle

3 0^{\circ}

with respect to the x-axis.

(D)

The refractive index of the medium is 2.

JEE Advanced 2025

LEVELJEE Main

A cube of unit volume contains $35 \times 1 0^{7}$ photons of frequency $1 0^{15} Hz$ . If the energy of all the photons is viewed as the average energy being contained in the electromagnetic waves within the same volume, then the amplitude of the magnetic field is $α \times 1 0^{- 9} T$ . Taking permeability of free space $μ_{0} = 4 π \times 1 0^{- 7} Tm/A$ , Planck's constant $h = 6 \times 1 0^{- 34} Js$ and $π = \frac{22}{7}$ , the value of $α$ is____

JEE Main 2026

LEVELJEE Advanced

The electric field associated with an electromagnetic wave travelling in vacuum is given by $E = E_{0} sin (3 y + 4 z + ω t) \hat{i}$ , where $ω$ is the angular frequency. All quantities are in SI units. The correct statement(s) about this wave is/are: [Given: speed of light in vacuum $c = 3 \times 1 0^{8} ms^{- 1}$ .]

* Multiple Correct Options

(A)

The wave is travelling in

- \frac{1}{5} (3 \hat{j} + 4 \hat{k})

direction.

(B)

The magnitude of the wave vector is

0.5 m^{- 1}

(C)

The value of

ω

1.5 \times 1 0^{9} rad s^{- 1}

(D)

The magnetic field associated with this wave is given by

\frac{E _{0}}{c} sin (3 y + 4 z + ω t) (4 \hat{j} - 3 \hat{k})

LEVELJEE Main

An electromagnetic wave in vacuum has the electric and magnetic fields $E$ and $B$ , which are always perpendicular to each other. The direction of polarisation is given by $X$ and that of wave propagation by $k$ . Then,

(A)

X ∥ B

and

k ∥ B \times E

(B)

X ∥ E

and

k ∥ E \times B

(C)

X ∥ B

and

k ∥ E \times B

(D)

X ∥ E

and

k ∥ B \times E

JEE Main 2021

LEVELBoard

A plane electromagnetic wave with frequency of $30 MHz$ travels in free space. At particular point in space and time, electric field is $6 V/m$ . The magnetic field at this point will be $x \times 1 0^{- 8} T$ . The value of $x$ is.

JEE Main 2019

LEVELBoard

A plane electromagnetic wave travels in free space along the x-direction. The electric field component of the wave at a particular point of space and time is $E = 6 Vm^{- 1}$ along y-direction. Its corresponding magnetic field component, $B$ would be

(A)

2 \times 1 0^{- 8} T

along z - direction

(B)

6 \times 1 0^{- 8} T

along x - direction

(C)

6 \times 1 0^{- 8} T

along z - direction

(D)

2 \times 1 0^{- 8} T

along y - direction

JEE Main 2020

LEVELJEE Main

In a plane electromagnetic wave, the directions of electric field and magnetic field are represented by $\hat{k}$ and $2 \hat{i} - 2 \hat{j}$ , respectively. What is the unit vector along direction of propagation of the wave?

(A)

\frac{1}{2} (\hat{i} + \hat{j})

(B)

\frac{1}{2} (\hat{j} + \hat{k})

(C)

\frac{1}{5} (\hat{i} + 2 \hat{j})

(D)

\frac{1}{5} (2 \hat{i} + \hat{j})

JEE Main 2019

LEVELJEE Main

50 W/m $^{2}$ energy density of sunlight is normally incident on the surface of a solar panel. Some part of incident energy (25%) is reflected from the surface and the rest is absorbed. The force exerted on 1 m $^{2}$ surface area will be close to ( $c = 3 \times 1 0^{8}$ m/s)

(A)

20 \times 1 0^{- 8}

(B)

35 \times 1 0^{- 8}

(C)

15 \times 1 0^{- 8}

(D)

10 \times 1 0^{- 8}

LEVELJEE Main

A radiation of energy $E$ falls normally on a perfectly reflecting surface. The momentum transferred to the surface is

(A)

\frac{E}{c}

(B)

\frac{2 E}{c}

(C)

E c

(D)

\frac{E}{c ^{2}}

JEE Main 2019

LEVELJEE Advanced

The magnetic field of a plane electromagnetic wave is given by $B = B_{0} [cos (k z - ω t)] \hat{i} + B_{1} cos (k z + ω t) \hat{j}$ where, $B_{0} = 3 \times 1 0^{- 5}$ T and $B_{1} = 2 \times 1 0^{- 6}$ T. The rms value of the force experienced by a stationary charge $Q = 1 0^{- 4}$ C at $z = 0$ is closest to

(A)

0.1 N

(B)

3 \times 1 0^{- 2}

The electric field intensity produced by the radiation coming from a $100 W$ bulb at a distance of $3 m$ is $E$ . The electric field intensity produced by the radiation coming from $60 W$ at the same distance is $\frac{x}{5} E$ , where the value of $x$ is ........... .

JEE Main 2019

LEVELJEE Advanced

A light wave is incident normally on a glass slab of refractive index 1.5. If 4% of light gets reflected and the amplitude of the electric field of the incident light is $30 V/m$ , then the amplitude of the electric field for the wave propogating in the glass medium will be

(A)

30 V/m

(B)

6 V/m

(C)

10 V/m

(D)

24 V/m

JEE Main 2021

LEVELJEE Advanced

A radiation is emitted by $1000 W$ bulb and it generates an electric field and magnetic field at $P$ , placed at a distance of $2 m$ . The efficiency of the bulb is $1.25%$ . The value of peak electric field at $P$ is $x \times 1 0^{- 1} V/m$ . Value of $x$ is ......... . (Rounded-off to the nearest integer) [Take, $ε_{0} = 8.85 \times 1 0^{- 12} C^{2} N^{- 1} m^{- 2}$ , $c = 3 \times 1 0^{8} ms^{- 1}$ ]

JEE Main 2020

LEVELJEE Main

For a plane electromagnetic wave, the magnetic field at a point $x$ and time $t$ is $B (x, t) = [1.2 \times 1 0^{- 7} sin (0.5 \times 1 0^{3} x + 1.5 \times 1 0^{11} t) \hat{k}] T$ . The instantaneous electric field $E$ corresponding to $B$ is (Given, speed of light, $c = 3 \times 1 0^{8} m/s$ )

(A)

E (x, t) = [- 36 sin (0.5 \times 1 0^{3} x + 1.5 \times 1 0^{11} t) \hat{j}] \frac{V}{m}

(B)

E (x, t) = [36 sin (1 \times 1 0^{3} x + 0.5 \times 1 0^{11} t) \hat{j}] \frac{V}{m}

(C)

E (x, t) = [36 sin (0.5 \times 1 0^{3} x + 1.5 \times 1 0^{11} t) \hat{k}] \frac{V}{m}

(D)

E (x, t) = [- 36 sin (1 \times 1 0^{3} x + 1.5 \times 1 0^{11} t) \hat{j}] \frac{V}{m}

JEE Main 2020

LEVELJEE Main

A plane electromagnetic wave of frequency $25 GHz$ is propagating in vacuum along the z-direction. At a particular point in space and time, the magnetic field is given by $B = 5 \times 1 0^{- 8} \hat{j} T$ . The corresponding electric field $E$ is (speed of light, $c = 3 \times 1 0^{8} ms^{- 1}$ )

(A)

- 1.66 \times 1 0^{- 16} \hat{i} V/m

(B)

1.66 \times 1 0^{- 16} \hat{i} V/m

(C)

- 15 \hat{i} V/m

(D)

15 \hat{i} V/m

JEE Main 2021

LEVELJEE Main

A plane electromagnetic wave propagating along $y$ -direction can have the following pair of electric field ( $E$ ) and magnetic field ( $B$ ) components.

(A)

E_{y}, B_{y}

E_{z}, B_{z}

(B)

E_{y}, B_{x}

E_{x}, B_{y}

(C)

E_{x}, B_{z}

E_{z}, B_{x}

(D)

E_{x}, B_{y}

E_{y}, B_{x}

JEE Main 2016

LEVELJEE Main

Arrange the following electromagnetic radiations per quantum in the order of increasing energy. A. Blue light B. Yellow light C. X-ray D. Radio wave

If the magnetic field of a plane electromagnetic wave is given by $B = 100 \times 1 0^{- 6} sin [2 π \times 2 \times 1 0^{15} (t - \frac{x}{c})]$ then the maximum electric field associated with it is (Take, the speed of light $= 3 \times 1 0^{8}$ m/s)

(A)

6 \times 1 0^{4}

N/C

(B)

4 \times 1 0^{4}

N/C

(C)

3 \times 1 0^{4}

N/C

(D)

4.5 \times 1 0^{4}

N/C

JEE Main 2020

LEVELJEE Main

If the magnetic field in a plane electromagnetic wave is given by $B = 3 \times 1 0^{- 8} sin (1.6 \times 1 0^{3} x + 48 \times 1 0^{10} t) \hat{j} T$ , then what will be expression for electric field?

(A)

E = 60 sin (1.6 \times 1 0^{3} x + 48 \times 1 0^{10} t) \hat{k} V/m

(B)

E = 3 \times 1 0^{- 8} sin (1.6 \times 1 0^{3} x + 48 \times 1 0^{10} t) \hat{i} V/m

(C)

E = 3 \times 1 0^{- 8} sin (1.6 \times 1 0^{3} x + 48 \times 1 0^{10} t) \hat{j} V/m

(D)

E = 9 sin (1.6 \times 1 0^{3} x + 48 \times 1 0^{10} t) \hat{k} V/m

LEVELJEE Main

An electromagnetic wave of frequency $ν = 3.0 MHz$ passes from vacuum into a dielectric medium with permittivity $ε = 4.0$ . Then,

(A)

wavelength is doubled and the frequency remains unchanged

(B)

wavelength is doubled and frequency becomes half

(C)

wavelength is halved and frequency remains unchanged

(D)

wavelength and frequency both remain unchanged

LEVELJEE Main

The rms value of the electric field of the light coming from the sun is $720 NC^{- 1}$ . The average total energy density of the electromagnetic wave is

(A)

4.58 \times 1 0^{- 6} Jm^{- 3}

(B)

6.37 \times 1 0^{- 9} Jm^{- 3}

(C)

81.35 \times 1 0^{- 12} Jm^{- 3}

(D)

3.3 \times 1 0^{- 3} Jm^{- 3}

LEVELBoard

Which of the following are not electromagnetic waves?

(A)

cosmic rays

(B)

γ

-rays

(C)

β

-rays

(D)

X-rays

In an X-ray tube, electrons accelerated through a potential difference of 15, 000 V strike a copper target. The speed of the emitted X-ray inside the tube is ....... m/s.

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } A radiation of energy E falls normally on a perfectly reflecting surface. The momentum transferred to the surface is

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } A plane electromagnetic wave propagating along y-direction can have the following pair of electric field (E) and magnetic field (B) components.

Arrange the following electromagnetic radiations per quantum in the order of increasing energy. A. Blue light B. Yellow light C. X-ray D. Radio wave

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } If the magnetic field in a plane electromagnetic wave is given by B=3×10−8sin(1.6×103x+48×1010t)j^​ T, then what will be expression for electric field?

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } An electromagnetic wave of frequency ν=3.0 MHz passes from vacuum into a dielectric medium with permittivity ε=4.0. Then,

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } The rms value of the electric field of the light coming from the sun is 720 NC−1. The average total energy density of the electromagnetic wave is

Which of the following are not electromagnetic waves?

A radiation of energy $E$ falls normally on a perfectly reflecting surface. The momentum transferred to the surface is

A plane electromagnetic wave propagating along $y$ -direction can have the following pair of electric field ( $E$ ) and magnetic field ( $B$ ) components.

If the magnetic field in a plane electromagnetic wave is given by $B = 3 \times 1 0^{- 8} sin (1.6 \times 1 0^{3} x + 48 \times 1 0^{10} t) \hat{j} T$ , then what will be expression for electric field?

An electromagnetic wave of frequency $ν = 3.0 MHz$ passes from vacuum into a dielectric medium with permittivity $ε = 4.0$ . Then,

The rms value of the electric field of the light coming from the sun is $720 NC^{- 1}$ . The average total energy density of the electromagnetic wave is