Question

The velocity of all radio waves in free space is $3 \times 10^{8} m / s$. The frequency of a radio wave of wavelength $150\, m$ is :

• A. 20 kHz
• B. 2 kHz
• C. 2 MHz
• D. 1 MHz

Answer 1

Answer: (C)

Here : Velocity of electromagnetic waves in free space and wavelength
$v =3 \times 10^{8} m / s$
$\lambda =150\, m$
Using the relation for the frequency of radio waves is given by
$=\frac{v}{\lambda}=\frac{3 \times 10^{8}}{150}$
$=2 \times 10^{6} Hz =2\, MHz$