A plane electromagnetic wave of frequency 40 MHz travels in free space in the X-direction. At some point and at some instant, the electric field $\vec{E}$ has its maximum value of 750 N/C in Y-direction.

The angular frequency of e.m.f. wave will be:(in rad/s)

$8\pi \times 10^7$ $4\pi \times 10^6$ $4\pi \times 10^5$ $8\pi \times 10^4$

$8\pi \times 10^7$

$ \omega = 2\pi f = 2\pi \times 4\times 10^7 = 8\pi \times 10^7 rad/s$