Question

The electric field of a uniform plane electromagnetic wve in free space, along the positive direction, is given by E = 10(ay + jaz)e^-j25x. The frequency and polarization of the wave, respectively are

(a) 1.2 GHz, left circular

(b) 4 GHz, left circular

(c) 1.2 GHz, right circular

(d) 4 GHz, right circular

This question was posed to me in an interview for internship.

My query is from Advanced and Tricky Questions in section Advanced and Tricky Questions of Electromagnetic Theory

Answer 1

The correct choice is (a) 1.2 GHz, left circular

The best explanation: The amplitudes of the components are the same. Hence it is circular polarization. The phase difference is +90 degree. Thus it is left hand circular polarisation. The frequency f = c/wavelength = 3 x 10^8 x 25/2 x 3.14 = 1.2 GHz.