List of top Physics Questions on Electromagnetic waves asked in JEE Main

Monochromatic light of frequency $6 \times 10^{14}$ Hz is produced by a laser. The power emitted is $2 \times 10^{-3}$ W. How many photons per second on average are emitted by the source.(Given $h = 6.63 \times 10^{-34} \, \text{Js}$)

If frequency of electromagnetic wave is 60 MHz and it travels in air along z direction then the corresponding electric and magnetic field vectors will be mutually perpendicular to each other and the wavelength of the wave (in m) is :

Electromagnetic waves travel in a medium with a speed of \( 1.5 \times 10^8 \, \text{ms}^{-1} \). The relative permeability of the medium is \( 2.0 \). The relative permittivity will be:

In the given electromagnetic wave \[ E_y = 600 \sin(\omega t - kx) \, \text{V/m}, \] intensity of the associated light beam is (in W/m$^2$); (Given $\epsilon_0 = 9 \times 10^{-12} \, \text{C}^2 \text{N}^{-1} \text{m}^{-2}$).

Match List-I with List-II :-

List-I EM-Wave	List-II Wavelength Range
(A) Infra-red	(III) 1 mm to 700 nm
(B) Ultraviolet	(II) 400 nm to 1 nm
(C) X-rays	(IV) 1 nm to \(10^{-3}\) nm
(D) Gamma rays	(I) \(<10^{-3}\) nm

Choose the correct answer from the options given below :

The electric field in an electromagnetic wave is given by \[ \vec{E} = \hat{i} 40 \cos \omega \left( t - \frac{z}{c} \right) \, \text{NC}^{-1}.\]The magnetic field induction of this wave is (in SI unit):

An electron is projected with uniform velocity along the axis inside a current carrying long solenoid. Then :

Match List I with List II

Choose the correct answer from the options given below :

A plane EM wave is propagating along x direction. It has a wavelength of 4 mm. If electric field is in y direction with the maximum magnitude of 60 V m^-1, the equation for magnetic field is:

In a plane EM wave, the electric field oscillates sinusoidally at a frequency of \( 5 \times 10^{10} \, \text{Hz} \) and an amplitude of \( 50 \, \text{Vm}^{-1} \). The total average energy density of the electromagnetic field of the wave is: \([ \text{Use } \epsilon_0 = 8.85 \times 10^{-12} \, \text{C}^2 / \text{Nm}^2 ]\)

Given below are two statements:
Statement I: Electromagnetic waves carry energy as they travel through space and this energy is equally shared by the electric and magnetic fields.
Statement II: When electromagnetic waves strike a surface, a pressure is exerted on the surface. In the light of the above statements.
Choose the most appropriate answer from the options given below:

The magnetic field in a plane electromagnetic wave is \[ B_y = (3.5 \times 10^{-7}) \sin \left( 1.5 \times 10^3 x + 0.5 \times 10^{11} t \right) \, \text{T}. \] The corresponding electric field will be:

An object is placed in a medium of refractive index 3. An electromagnetic wave of intensity \(6 \times 10^8 \, \text{W/m}^2\) falls normally on the object and it is absorbed completely. The radiation pressure on the object would be (speed of light in free space = \(3 \times 10^8\) m/s) :

A particle is moving in a straight line. The variation of position \( x \) as a function of time \( t \) is given as\[x = (t^3 - 6t^2 + 20t + 15) \, \text{m}.\]The velocity of the body when its acceleration becomes zero is:

A plane electromagnetic wave propagating in x-direction is described by \( E_y = (200 \, \text{V/m}) \sin(1.5 \times 10^7 t - 0.05 x) \). The intensity of the wave is:

The electric field of an electromagnetic wave in free space is represented as \( \vec{E} = E_0 \cos(\omega t - kz) \hat{i} \). The corresponding magnetic induction vector will be:

An electromagnetic wave has electric field given by  \(\overrightarrow E = (9.6 \hat j)sin \bigg[2π\; {30 × 10^6t -\frac{1}{10} x}\bigg]\), \(x\) and \(t\) are in SI units. The maximum magnetic field is

A source produced electromagnetic wave of frequency 60MHz. Find the wavelength of this wave in air.

Calculate the average energy density of an electromagnetic wave whose electric field is oscillating with amplitude \(50 \;V/m\) and frequency \(5 \times10^{10}\) \(Hz\) :

In an electromagnetic wave electric field and magnetic field is given by
E = E₀ sin (kx – ωt + ϕ)
B = B₀ sin (kx – ωt + ϕ)
Find correct relation.

If a source of electromagnetic radiation having power $15 kW$ produces $10^{16}$ photons per second, the radiation belongs to a part of spectrum is(Take Planck constant $h =6 \times 10^{-34} Js$ )

Match List I with List II

List I		List II
A.	Microwaves	I.	Physiotherapy
B.	UV rays	II.	Treatment of cancer
C.	Infra-red rays	III.	Lasik eye surgery
D.	X-rays	IV.	Aircraft navigation

Choose the correct answer from the options given below:

An electromagnetic wave is transporting energy in the negative $z$ direction At a certain point and certain time the direction of electric field of the wave is along positive $y$ direction What will be the direction of the magnetic field of the wave at that point and instant?

In $\vec{E}$ and $\vec{K}$ represent electric field and propagation vectors of the EM waves in vacuum, then magnetic field vector is given by:$(\omega-$ angular frequency):