Question

The power of a wave having a magnetic field intensity of 2.5 units is

(a) 1.17 kilo watt

(b) 1.17 mega watt

(c) 1.17 watt

(d) 11.7 watt

I had been asked this question during an interview.

My question comes from Transients in division Waveguides of Electromagnetic Theory

Answer 1

Right answer is (a) 1.17 kilo watt

The explanation: The power of a wave is given by P = 0.5 η H^2, where η is the intrinsic impedance and H is the magnetic field intensity. On substituting for η = 377 and H = 2.5, we get P = 0.5 x 377 x 2.5^2 = 1.17 kilo watts.