Question

The electric field part of an electromagnetic wave in vacuum is
$E = 3.1 \frac{N}{C} cos \left[\left(1.8 \frac{rad}{m}\right) y + \left(5.4 \times 10^{8} \frac{rad}{s}\right)t\right] \hat{i}$, the frequency corresponding to the given part of electromagnetic wave is

• A. $5.4 \times 10^8 \,Hz$
• B. $8.6 \times 10^7 \,Hz$
• C. $3.2 \times 10^8 \,Hz$
• D. $4.8 \times 10^7 \,Hz$

Answer 1

Answer: (B)

Frequency,
$\upsilon = \frac{\omega}{2\pi} = \frac{5.4 \times 10^{8} \times 7}{2 \times 22}$
$= 8.6 \times 10^{7} \,Hz$