Radio waves have velocity of \(3 \times 10^{8} ms ^{-1}\). If a radio station sends out a broadcast on a frequency \(800 KHz\), what is the wavelength of the broadcast?
A. \(375.0 m\) B. \(267.0 m \) C. \(240.0 m\) D. \(37.5 m\) E. \(26.7 m\)
Correct Answer: A
Explanation
$$ \begin{aligned} v &=3 \times 10^{8} m / s , f =800 kHz , \\ \lambda &=?, v=f \lambda \\ \lambda &=\frac{v}{f}=\frac{3 \times 10^{8}}{800 \times 10^{3}} \\ \lambda &=0.375 \times 10^{3} m / s \\ &=375 m \end{aligned} $$
