Physics Crash Course JEE Main>Chapter 17 - Electromagnetic Waves>Level 3>Q 5

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IMPORTANT

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The electric field of a plane electromagnetic wave in vacuum is represented by,
$E_{x} = 0, E_{y} = 0.5 \cos [2 π \times 10^{8} (t - \frac{x}{c})]$ and $E_{z} = 0$ . Which option is incorrect?

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Important Questions on Electromagnetic Waves

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Physics Crash Course JEE Main>Chapter 17 - Electromagnetic Waves>Level 1>Q 7

If the speed of gamma rays, X-rays and microwaves in free space are

V_{g}

,

V_{x}

and

V_{m}

, respectively, then the correct relation is

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Physics Crash Course JEE Main>Chapter 17 - Electromagnetic Waves>Level 1>Q 17

The frequencies of

X

-rays,

γ

-rays and ultraviolet rays are respectively

a, b

and

c

. Then

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Physics Crash Course JEE Main>Chapter 17 - Electromagnetic Waves>Level 3>Q 6

A

160 W

infrared source is radiating light of wavelength

50000 \overset{°}{A}

uniformly in all directions. The photon flux at a distance of

1.8 m

is of the order of,

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Physics Crash Course JEE Main>Chapter 17 - Electromagnetic Waves>Level 1>Q 3

A plane electromagnetic wave of frequency

50 MHz

, travels in free space along the positive

x

-direction. At a particular point in space and time, the electric field is

\vec{E} = 6.3 \hat{j} V m^{- 1}

. The corresponding magnetic field

\vec{B}

, at the point will be

z \times 10^{- 8} \hat{k} T

, what is the value of

z

?

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Physics Crash Course JEE Main>Chapter 17 - Electromagnetic Waves>Level 1>Q 4

An EM wave enters from medium-(1) to medium-(2). The electric fields are

{\vec{E}}_{1} = E_{01} \sin (kx - ωt) \hat{j}

in medium-(1) &

{\vec{E}}_{2} = E_{02} \sin (3 kx - ωt) \hat{j}

in medium

- (2) .

If

\frac{μ_{r_{1}}}{μ_{r_{2}}} = \frac{1}{4}

and

\frac{ϵ_{r_{2}}}{ϵ_{r_{1}}} = \frac{n}{4}

, then find the value of

n

. (

μ_{r} & ϵ_{r}

are relative permeability & permittivity of medium)

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Physics Crash Course JEE Main>Chapter 17 - Electromagnetic Waves>Level 1>Q 5

Monochromatic light of frequency

6.0 \times 10^{14} Hz

is produced by a laser. The power emitted is

2 \times 10^{- 3} W

. The number of photons emitted on an average by the source per second is

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Physics Crash Course JEE Main>Chapter 17 - Electromagnetic Waves>Level 1>Q 20

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.

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Physics Crash Course JEE Main>Chapter 17 - Electromagnetic Waves>Level 1>Q 21

Name the EM wave used for studying crystal structure of solids