Question

An electromagnetic wave has a frequency of 500 MHz and a wavelength of 60 cm, then find the speed of the wave.

• A. $6\times {10}^{8}m/s$
• B. $3\times {10}^{8}m/s$
• C. $9\times {10}^{8}m/s$
• D. $12\times {10}^{8}m/s$

Answer 1

The correct option is B

$3\times {10}^{8}m/s$

$\text{We have f}=\frac{\text{c}}{\lambda }$ [$\text{frequency}=\frac{\text{speed}}{\text{wave length}}$]

$\text{c}=\text{f}\times \lambda$

$\Rightarrow \text{c}=500\times {10}^6\times 60\times {10}^{-2}$

$\Rightarrow \text{c}=3\times {10}^{8}m/s$