Question

The electric fields part of an electromagnetic wave I vacuum is E=3.1 $\mathrm { C } ^ { - 1 }$ $\cos\left\lbrack (1.8radm^{- 1})y + (5.4 \times 18^{8}rads^{- 1})t \right\rbrack\widehat{i}$ 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)

$8.6 \times 10^{7}Hz$

Answer 2

: Frequency,

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