Question

The magnetic field in a plane electromagnetic wave is given By = 2 × 10–7 sin (0.5 × 103x + 1.5 × 1011t)T. The expression for electric field is

(A) Ex = 60 sin(0.5 × 103x + 1.5 × 1011t)Vm–1

(B) Ez = 60 sin(0.5 × 103x + 1.5 × 1011t)Vm–1

(C) Ez = 60 sin(1.5 × 1011x + 0.5 × 103t)Vm–1

(D) Ez = 60 × 1015 sin(1.5 × 1011x + 0.5 × 103t)Vm–1

Answer 1

The correct option is (B) Ez = 60 sin(0.5 × 103x + 1.5 × 1011t)Vm–1

Explanation:

By = 2 × 10–7 sin (0.5 × 103x + 1.5 × 1011t)

Electric field component is perpendicular to direction of propagation and direction of magnetic field will be along z axis.

∴ (Eo / Bo) = C hence Eo = C × Bo

∴ Eo = 3 × 108 × 2 × 10–7 = 60 V/m

∴ Ez = 60 sin(0.5 × 103x + 1.5 × 1011t)V/m