### NEET Physics - New - Electromagnetic Waves

#### Question - 1

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:

• A - y direction
• B + z direction
• C - z direction
• D - x direction

#### Question - 2

In an electromagnetic wave in free space the root mean square value of the electric field is Erms = 6 V/m. The peak value of the magnetic field is:

• A 1.41 x 10-8 T
• B 2.83 x 10-8 T
• C 0.70 x 10-8 T
• D 4.23 x 10-s T

#### Question - 3

Out of the following options which one can be used to produce a propagating electromagnetic wave?

• A Achargeless particle
• B An accelerating charge
• C Acharge moving at constant velocity
• D A stationary charge

#### Question - 4

Aradiation of energy E falls normally on a perfectly reflecting surface. The momentum transferred to the surface is : (e = Velocity of light)

• A E/c2
• B E/c
• C 2E/c
• D 2E/c2

#### Question - 5

Light with an energy flux of 25 x 104 Wm-2 falls on a perfectly reflecting surface at normal incidence. If the surface area is 15 Cm2, the average force exerted on the surface is :

• A 1.20 x 10-6 N
• B 3.0 x 10-6 N
• C 1.25 x 10-6 N
• D 2.50 x 10-6 N

#### Question - 6

A wave travelling in the +ve x-direction having displacement along y-direction as 1 m, wavelength 27 Tm and frequency of 1/πHz is represented by:

• A y = sin (x - 2t)
• B y= sin (2π x- 2πt)
• C y = sin (10πx - 20πt)
• D y = sin (27πX + 2πt)

#### Question - 7

The condition under which a microwave oven heats up a food item containing water molecules most efficiently is :

• A The frequency of the microwaves must match the resonant frequency of the water molecules
• B The frequency of the microwaves has no relation with natural frequency of water mole
• C Microwaves are heat waves, so always produce heating
• D Infra-red waves produce heating in a microwave oven

#### Question - 8

The electric and the magnetic field, associated with an e.m. wave, propagating along the +z-axis, can be represented by

• A E =Eo k, B = B0 i
• B E =Eo j, B = B0 i
• C E = E0 j , B = B0 k
• D E =E0 i, B = B0 j

#### Question - 9

The decreasing order of wavelength of infrared, microwave, ultraviolet and gamma rays is

• A microwave, infrared, ultraviolet, gamma rays
• B gamma rays, ultraviolet, infrared, microwaves
• C microwaves, gamma rays, infrared, ultraviolet
• D infrared, microwave, ultraviolet, gamma rays

#### Question - 10

The ionization energy of the electron in the hydrogen atom in its ground state is 13.6 eV. The atoms are excited to higher energy levels to emit radiations of 6wavelengths. Maximum wavelength of emitted radiation corresponds to the transition between:

• A n = 3 to n = 1 states
• B n = 2 to n = 1 states
• C n = 4 to n = 3 states
• D n = 3 to n = 2 states