CBSE Class 12 · 2007 · EM WavesShort Answer

Write any four characteristics of electromagnetic waves. Give two uses each of
(i) radio waves and
(ii) microwaves.

Solution

Four characteristics of electromagnetic waves:
(i) They are transverse ---

E

and

B

oscillate perpendicular to the direction of propagation.
(ii) They require no material medium and travel through vacuum at

c = 3 \times 1 0^{8}

m/s.
(iii)

E

and

B

are mutually perpendicular and in phase, with

E_{0} = c B_{0}

.
(iv) They carry energy and momentum and, being neutral, are not deflected by electric or magnetic fields.
Uses of radio waves: (a) radio and television broadcasting and communication; (b) radio astronomy.
Uses of microwaves: (a) RADAR and aircraft navigation; (b) microwave ovens (and satellite communication).

transverse, no medium, E_{0} = c B_{0}, carry energy/momentum

CBSE Class 12 Board · 2007 · Subjective

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