Question

The magnetic field in a plane electromagnetic wave is given by

B_y = 12 x 10^-8 sin (1.20 x 10⁷ z + 3.60 x 10¹⁵ t) T:

Calculate the

(i) Energy density associated with the electromagnetic wave

(ii) Speed of wave

Answer 1

(i) Energy density u = \(\frac{B^2}{\mu_0}\) = 11.5 x 10^-9 Jm^-3

Speed of the wave v = \(\frac{\omega}{k}\) = C = 3x 10⁸ ms^-1.