A monochromatic beam of light has a frequency v = 3 2 π × 10 12 Hz and is propagating along the direction i ^ + j ^ 2 . It is polarized along the k ^ direction. The acceptance form the magnetic field is:

E 0 C i ^ - j ^ 2 Cos ⁡ 10 4 i ^ + j ^ 2 . r → + 3 × 10 12 t

E 0 C i ^ + j ^ 2 Cos ⁡ 10 4 i ^ + j ^ 2 . r → - 3 × 10 12 t

E 0 C k ^ Cos ⁡ 10 4 i ^ + j ^ 2 . r → + 3 × 10 12 t

E 0 C i ^ + j ^ + k ^ 3 Cos ⁡ 10 4 i ^ + j ^ 2 . r → + 3 × 10 12 t

The magnetic field of an electromagnetic wave is given by: B → = 1.6 × 10 - 6 cos ⁡ 2 × 10 7 z + 6 × 10 15 t 2 i ^ + j ^ W b m 2 The associated electric field will be:

E → = 4.8 × 10 2 c o s 2 × 10 7 z + 6 × 10 15 t - i ^ + 2 j ^ V m

E → = 4.8 × 10 2 c o s 2 × 10 7 z - 6 × 10 15 t - 2 j ^ + i ^ V m

E → = 4.8 × 10 2 c o s 2 × 10 7 z + 6 × 10 15 t i ^ - 2 j ^ V m

E → = 4.8 × 10 2 c o s 2 × 10 7 z - 6 × 10 15 t 2 i ^ + j ^ V m

Magnetic field in a plane electromagnetic wave is given by, B → = B 0 sin k x + ω t j ^ T . Expression for corresponding electric field will be: (Where c is speed of light)

E → = B 0 c sin k x + ω t k ^ V m - 1

E → = - B 0 c sin k x + ω t k ^ V m - 1

E → = B 0 c sin k x - ω t k ^ V m - 1

E → = B 0 c sin k x + ω t k ^ V m - 1

The electric field of a plane polarized electromagnetic wave in free space at time t = 0 is given by the expression E → x , y = 10 j ^ c o s 6 x + 8 z . The magnetic field B → x , z , t is given by ( c is the velocity of light.)

1 c 6 k ^ - 8 i ^ c o s 6 x + 8 z - 10 c t

1 c 6 k ^ - 8 i ^ cos 6 x + 8 z + 10 c t

1 c 6 k ^ + 8 i ^ cos 6 x + 8 z - 10 c t

1 c 6 k ^ + 8 i ^ cos 6 x - 8 z + 10 c t

EASY

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Consider a point charge +q moving with a constant velocity $\vec{v} = v \hat{k}$ in vacuum in the presence of an electric field $\vec{E} = E_{x} \hat{i} + E_{y} \hat{j}$ and a magnetic field $\vec{B} = B_{x} \hat{i} + B_{y} \hat{j}$ . Unit vectors $\hat{i}, \hat{j}$ and $\hat{k}$ are in the directions of $x, y$ and $z$ axes, respectively. Which of the following relations is correct?

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Important Questions on Electromagnetic Waves

EASY

Physics>Electricity and Magnetism>Electromagnetic Waves>Electromagnetic Wave and Their Characteristics

An EM wave is propagating in a medium with a velocity

\vec{V} = V \hat{i}

. The instantaneous oscillating electric field of this em wave is along

+ y

axis. Then the direction of oscillating magnetic field of the EM wave will be along

MEDIUM

Physics>Electricity and Magnetism>Electromagnetic Waves>Electromagnetic Wave and Their Characteristics

An electromagnetic wave travelling in the

x -

direction has frequency of

2 \times 10^{14} H z

and electric field amplitude of

27 V m^{- 1}

oscillates in

Y -

direction. From the options given below, which one describes the magnetic field for this wave?

MEDIUM

Physics>Electricity and Magnetism>Electromagnetic Waves>Electromagnetic Wave and Their Characteristics

A radio transmitter sends out

60 W

of radiation. Assuming that the radiation is uniform on a sphere with the transmitter at its centre, the intensity

(i n W / m^{2})

of the wave at a distance

12 k m

HARD

Physics>Electricity and Magnetism>Electromagnetic Waves>Electromagnetic Wave and Their Characteristics

A monochromatic beam of light has a frequency

v = \frac{3}{2 π} \times 10^{12}

Hz

and is propagating along the direction

\frac{\hat{i} + \hat{j}}{\sqrt{2}}

. It is polarized along the

\hat{k}

direction. The acceptance form the magnetic field is:

EASY

Physics>Electricity and Magnetism>Electromagnetic Waves>Electromagnetic Wave and Their Characteristics

If the magnetic field of a plane electromagnetic wave is given by (The speed of light

= 3 \times 10^{8} m s^{- 1}

)

B = 100 \times 10^{- 6} \sin [2 π \times 2 \times 10^{15} (t - \frac{x}{c})]

then the maximum electric field associated with it is:

HARD

Physics>Electricity and Magnetism>Electromagnetic Waves>Electromagnetic Wave and Their Characteristics

The electric field component of a monochromatic radiation is given by

\vec{E} = 2 E_{0} \cos k z \cos ω t \hat{i}

, Its magnetic field

\vec{B}

is then given by:

MEDIUM

Physics>Electricity and Magnetism>Electromagnetic Waves>Electromagnetic Wave and Their Characteristics

For plane electromagnetic waves propagating in the

+ z

-direction, which one of the following combinations gives the correct possible direction for

\vec{E}

and

\vec{B}

field respectively?

MEDIUM

Physics>Electricity and Magnetism>Electromagnetic Waves>Electromagnetic Wave and Their Characteristics

The magnetic field of an electromagnetic wave is given by:

\vec{B} = 1.6 \times 10^{- 6} \cos (2 \times 10^{7} z + 6 \times 10^{15} t) (2 \hat{i} + \hat{j}) \frac{W b}{m^{2}}

The associated electric field will be:

MEDIUM

Physics>Electricity and Magnetism>Electromagnetic Waves>Electromagnetic Wave and Their Characteristics

The energy associated with electric field is

(U_{E})

and with magnetic field is

(U_{B})

for an electromagnetic wave in free space. Then:

MEDIUM

Physics>Electricity and Magnetism>Electromagnetic Waves>Electromagnetic Wave and Their Characteristics

The mean intensity of radiation on the surface of the Sun is about

10^{8} W m^{- 2} .

The RMS value of the corresponding magnetic field is closest to:

EASY

Physics>Electricity and Magnetism>Electromagnetic Waves>Electromagnetic Wave and Their Characteristics

In an electromagnetic wave in free space the root mean square value of the electric field is

E_{r m s} = 6 V m^{- 1}

. The peak value of the magnetic field is

MEDIUM

Physics>Electricity and Magnetism>Electromagnetic Waves>Electromagnetic Wave and Their Characteristics

A red $L E D$ emits light at $0.1 watt$ uniformly around it. The amplitude of the electric field of the light at a distance of $1 m$ from the diode is:

EASY

Physics>Electricity and Magnetism>Electromagnetic Waves>Electromagnetic Wave and Their Characteristics

During the propagation of electromagnetic wave in a particular medium :-

MEDIUM

Physics>Electricity and Magnetism>Electromagnetic Waves>Electromagnetic Wave and Their Characteristics

Magnetic field in a plane electromagnetic wave is given by,

\vec{B} = B_{0} \sin (k x + ω t) \hat{j} T

. Expression for corresponding electric field will be:

(Where

c

is speed of light)

EASY

Physics>Electricity and Magnetism>Electromagnetic Waves>Electromagnetic Wave and Their Characteristics

Consider an electromagnetic wave propagating in vacuum. Choose the correct statement:

HARD

Physics>Electricity and Magnetism>Electromagnetic Waves>Electromagnetic Wave and Their Characteristics

The magnetic field of a plane electromagnetic wave is given by

\vec{B} = B_{0} \hat{i} [c o s (k z - ω t)] + B_{1} \hat{j} c o s (k z + ω t)

, where

B_{0} = 3 \times 10^{- 5} T

and

B_{1} = 2 \times 10^{- 6} T

. The

RMS

value of the force experienced by a stationary charge

Q = 10^{- 4} C

z = 0

is closest to

EASY

Physics>Electricity and Magnetism>Electromagnetic Waves>Electromagnetic Wave and Their Characteristics

An electromagnetic wave is represented by the electric filed

\vec{E} = E_{0} \hat{n} \sin [ω t + (6 y - 8 z)] .

Taking unit vectors in

x, y

and

z

directions to be

\hat{i}, \hat{j}, \hat{k},

the directions of propagations

\hat{s},

is:

EASY

Physics>Electricity and Magnetism>Electromagnetic Waves>Electromagnetic Wave and Their Characteristics

The magnetic field in a travelling electromagnetic wave has a peak value of

20 nT

. The peak value of electric field strength is :

HARD

Physics>Electricity and Magnetism>Electromagnetic Waves>Electromagnetic Wave and Their Characteristics

The electric field of a plane polarized electromagnetic wave in free space at time

t = 0

is given by the expression

\vec{E} (x, y) = 10 \hat{j} c o s (6 x + 8 z)

. The magnetic field

\vec{B} (x, z, t)

is given by (

c

is the velocity of light.)

MEDIUM

Physics>Electricity and Magnetism>Electromagnetic Waves>Electromagnetic Wave and Their Characteristics

A plane electromagnetic wave of frequency

50 M H z

travels in free space along the positive

x

- direction. At a particular point in space and time,

\vec{E} = 6.3 \hat{j} V / m,

The corresponding magnetic field

\vec{B}

, at that point will be:

Consider a point charge +q moving with a constant velocityv→=vk^ in vacuum in the presence of an electric field E→=Exi^+Eyj^ and a magnetic field B→=Bxi^+Byj^. Unit vectors i^,j^ and k^ are in the directions of x,y and z axes, respectively. Which of the following relations is correct?

Important Questions on Electromagnetic Waves

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