Question

The distance between two crests of a long radio wave is 2.50 km. What is  the frequency of this wave?

Answer 1

Solution.

$\lambda=2.50km=2500m;$

$c=3\sdot10^8m/s;$

$\lambda=c/\nu\implies \nu=c/\lambda;$

$\nu=\dfrac{3\sdot10^8m/s}{2500m}=1.2\sdot10^5Hz;$

Answer:$\nu=1.2\sdot 10^5Hz.$