In an electromagnetic wave both the electric and magnetic fields are perpendicular to the direction of propagation, that is why electromagnetic waves are transverse in nature. Electromagnetic waves carry energy as they travel through space and this energy is shared equally by the electric and magnetic fields. Energy density of an electromagnetic waves is the energy in unit volume of the space through which the wave travels.
(i) The electromagnetic waves propagated perpendicular to both \(\vec{E} \text { and } \vec{B}\). The electromagnetic waves travel in the direction of

(ii) Fundame tal particle in an electromagnetic wave is

(iii) Electromagnetic waves are transverse in nature is evident by

(iv) For a wave propagating in a medium, identify the property that is independent of the others.

(v) The electric and magnetic fields of an electromagnetic waves are

Maxwell showed that the speed of an electromagnetic wave depends on the permeability and permittivity of the medium through which it travels. The speed of an electromagnetic wave in free space is given by \(c=\frac{1}{\sqrt{\mu_{0} \varepsilon_{0}}} .\)The fact led Maxwell to predict that light is an electromagnetic wave. The emergence of the speed of light from purely electromagnetic considerations is the crowning achievement of Maxwell's electromagnetic theory. The speed of an electromagnetic wave in any medium of permeability \(\mu\) and permittivity \(\varepsilon\) will be \(\frac{c}{\sqrt{K \mu_{r}}}\) where K is the dielectric constant of the medium and \(\mu_r\) is the relative permeability.
(i) The dimensions of \(\frac{1}{2} \varepsilon_{0} E^{2}\) (\(\varepsilon_o\) permittivity of free space; E = electric field) is

(ii) Let [\(\varepsilon\)₀] denote the dimensional formula of the permittivity of the vacuum. If M = mass, L = length, T = time and A = electric current, then

(iii) An electromagnetic wave of frequency 3MHz passes from vacuum into a dielectric medium with permittivity \(\varepsilon\) = 4. Then

(iv) Which of the following are not electromagnetic waves?

(v) The electromagnetic waves travel with

An electromagnetic wave transports linear momentum as it travels through space. If an electromagnetic wave transfers a total energy U to a surface in time t, then total linear momentum delivered to the surface is \(p=\frac{U}{c}\) When an electromagnetic wave falls on a surface, it exerts pressure on the surface. In 1903, the American scientists Nichols and Hull succeeded in measuring radiation pressures of visible light where other had failed, by making a detailed empirical analysis of the ubiquitous gas heating and ballistic effects.
(i) The pressure exerted by an electromagnetic wave of intensity I (W m^-2) on a non-reflecting surface is (c is the velocity of light)

(ii) Light with an energy flux of 18 W/cm² falls on a non-reflecting surface at normal incidence. The pressure exerted on the surface is

(iii) Radiation of intensity 0.5 W m^-2 are striking a metal plate. The pressure on the plate is

(iv) A point source of electromagnetic radiation has an average power output of 1500 W The maximum value of electric field at a distance of3 m from this source (in V m^-1) is

(v) The radiation pressure of the visible light is of the order of

All the known radiations from a big family of electromagnetic waves which stretch over a large range of wavelengths. Electromagnetic wave include radio waves, microwaves, visible light waves, infrared rays, UV rays, X-rays and gamma rays. The orderly distribution of the electromagnetic waves in accordance with their wavelength or frequency into distinct groups having widely differing properties is electromagnetic spectrum.
(i) Which wavelength of the Sun is used finally as electric energy?

(ii) Which of the following electromagnetic radiations have the longest wavelength?

(iii) Which one of the following is not electromagnetic in nature?

(iv) Which of the following has minimum wavelength?

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

Electrons oscillating in a circuit give rise to radiowaves. A transmitting antenna radiates most effectively the radiowaves of wavelength equal to the size of the antenna. The infrared waves incident on a substance set into oscillation all its electrons, atoms and molecules. This increases the internal energy and hence the temperature of the substance.
(i) If v_g, v_x and vm are the speeds of gamma rays, X-rays and microwaves respectively in vacuum, then

(ii) Which of the following will deflect in electric field?

(iii) \(\Upsilon\)-rays are detected by

(iv) The frequency of electromagnetic wave, which best suited to observe a particle of radius 3 x 10^-4 cm is the order of

(v) We consider the radiation emitted by the human body. Which one of the following statements is true?

A stationary charge produces only an electrostatic field while a charge in uniform motion produces a magnetic field, that does not change with time. An oscillating charge is an example of accelerating charge. It produces an oscillating magnetic field, which in turruproduces an oscillating electric fields and so on. The oscillating electric and magnetic fields regenerate each other as a wave which propagates through space.

(i) Magnetic field in a plane electromagnetic wave is given by \(\vec{B}=B_{0} \sin (k x+\omega t) \hat{j} \mathrm{~T}\) Expression for corresponding electric field will be (Where C is speed of light.)

(ii) The electric field component of a monochromatic radiation is given by \(\vec{E}=2 E_{0} \hat{i} \cos k z \cos \omega t\) .Its magnetic field \(\vec{B}\) is then given by

(iii) A plane em wave of frequency 25 MHz travels in a free space along x-direction. At a particular point in space and time, \(E=(6.3 \hat{j}) \mathrm{V} / \mathrm{m}\) What is magnetic field at that time?

(iv) A plane electromagnetic wave travelling along the x-direction has a wavelength of 3 mm. The variation in the electric field occurs in the y-direction with an amplitude 66 V m^-1. The equations for the electric and magnetic fields as a function of x and t are respectively

(v) A plane electromagnetic wave travels in free space along x-axis. At a particular point in space, the electric field along y-axis is 9.3 V m^-1. The magnetic induction (B) along z-axis is

Radio waves are produced by the accelerated motion of charges in conducting wires. Microwaves are produced by special vacuum tubes. Infrared waves are produced by hot bodies and molecules also known as heat waves. UV rays are produced by special lamps and very hot bodies like Sun.

(i) Solar radiation is

(ii) What is the cause of greenhouse effect?

(iii) Biological importance of ozone layer is

(iv) Ozone is found in

(v) Earth's atmosphere is richest in