What is the frequency of a citizen's band(CB)radio which has a wavelength of 11.5meters?

Answer 1

Radio waves are electromagnetic waves and obey the relation
v=fλ
f=frequency (Hz)
λ=wavelength (m.)
v=velocity, m/s
and in vacuum,equals the speed of light for electromagnetic waves
c=3×10⁸ m/s
in air, v is slightly less than c.

So solve for f in the above equation.