a. What is an electromagnetic spectrum ?
b. How the electromagnetic waves are arranged ?
c. Mention some of the properties of E.M waves.

Explanation

a. Electromagnetic waves cover a wide range of frequencies or wavelengths. An ordely arrangement of electromagnetic radiations from gamma rays of very short wavelength to radio waves of long wavelength is known as electromagnetic spectrum.
b. In the order of increasing wavelength, they are arranged as `gamma` - rays, X - rays, U.V. rays, visible light, infrared radiations, microwaves and radio waves.
c. i. Produced by accelerated charges.
ii. Do not require any material for propagation.
iii. Velocity of electromagnetic waves in free space is equal to that of light in free space.
iv. Obey the principle of superposition.
v. They carry energy as they propagate through space.