Question

The velocity of electromagnetic waves in free space is $3 \times 10^{8} \,m / sec$. The frequency of a radio wave of wave length $150\, m$, is

• A. 20 kHz
• B. 45 MHz
• C. 2 kHz
• D. 2 MHz

Answer 1

Answer: (D)

2 MHz

Answer 2

Given: Velocity of electromagnetic waves in free space $(v)=3 \times 10^{8}\, m / \,sec$ and wavelength $(\lambda)$ $=150\, m .$ We know that frequency $(f)=\frac{v}{\lambda}=\frac{3 \times 10^{8}}{150}$ $= 2 \times 10^{6} \,Hz =2\, MHz$