U E = 1 / 2 ε o E 2 = 1 / 4 ε o E 2 o
( viii) The average magnetic energy
density, U B = 1 / 2 B 2 / μ o = 1 / B 2 o / μ o
( ix) The electric vector is responsible for the optical effects of an electromagnetic wave.
( x) Intensity of electromagnetic wave is defined as energy crossing per unit area per unit time perpendicular to the directions of propagation of electromagnetic wave.
( xi) The intensity I is given by the relation, I = < μ > c = 1 / 2 ε o E 2 oc
( xii) The existence of electromagnetic waves was confirmed by Hertz experimentally in 1888.
Propagation of Electromagnetic Waves
In radio wave communication between two places. the electromagnetic waves are radiated out by the transmitter antenna at one place which travel through the space and reach the receiving antenna at the other place.
Electromagnetic Spectrum