At what frequency should the radio transmitter work for its wavelength to be 150 m.

λ = 150 m.
s = 3 * 10 ^ 8 m / s.
v -?
Radio waves are electromagnetic radiation, so their speed of propagation in air is equal to the speed of light in vacuum.
The speed of propagation of waves is determined by the formula: c = λ * v, where λ is the wavelength, v is the frequency of the wave.
Let us express the frequency: v = s / λ.
v = 3 * 10 ^ 8 m / s / 150 m = 0.02 * 10 ^ 8 Hz = 0.2 GHz.
Answer: the radio transmitter must operate at a frequency of v = 0.2 GHz.