D.None of these
Write any four characteristics of electromagnetic waves. Give two uses of(i) radio-waves (ii) Microwaves.
Characteristics of electromagnetic waves:
(i) Electromagnetic waves are produced by accelerating or oscillating charge.
(ii) E.M. waves do not require any material medium for their propagation.
(iii) E.M. waves travel in free space with a velocitywhich is equal to the velocity of light(c = 3 × 108m/s).
(iv) E.M. waves are transverse in nature.
Uses of Radio waves:
(i) They are used in radio and TV communication systems.
(ii) Cellular phones use radio waves to transmit voice communication in the ultrahigh frequency (UHF) band.
Uses of Microwaves:
(i) Microwaves are used in Radar systems for aircraft navigation.
(ii) Microwave ovens are used for cooking purposes.