Question

In free space, E(z,t) = 10^3sin(ωt – βz) (hat{y}). Obtain H(z,t).

(a) 1.23 sin (ωt – βz) (-(hat{y}))

(b) 1.23 sin(ωt – βz) (-(hat{x}))

(c) 2.65 sin (ωt – βz) (-(hat{y}))

(d) 2.65 sin(ωt – βz) (-(hat{x}))

Answer 1

Correct option is (d) 2.65 sin(ωt – βz) (-(hat{x}))

Easiest explanation: In the following case, the wave is propagating in z direction. Therefore, direction of S is in z direction.

We know, S = E X B. As E is in +ve y direction, B should be in negative x direction,

Also we know, (mid Emid /mid Hmid) = 376.6

Therefore, (mid Hmid) = 10^3/376.6

( mid Hmid) = 2.65

Hence, H(z,t) = 2.65 sin(wt – az) – (hat{x}).