Question

What is the frequency of an electromagnetic wave if it has a wavelength of 1.2 km? the speed of light is 3 × 108 m/s. answer in units of hz?

Answer 1

λν=c where λ is the wavelength, ν is the frequency and c is the speed of light;
if λ = 1.2km = 1.2×10^3 m, then:
λν=c, and ν = c/λ

`v = (3.0 * {10}^(8))m/s / (1.2 * {10}^(3))m \\ v = 2.5 * {10}^(5) \: \: 1/s = {s}^( - 1) = hz`