Given: The wavelength of radio wave is x and frequency is y.
Here, frequency (y) = 3.0×10⁹ Hz
And the velocity of the radio wave which is equal to the velocity of light (v) = 3.0×10⁸ m/s
Since, wavelength and frequency is inversely proportional to each other then
x ∝ (1/y)
or, x = v /y ----------------(1)
Here, v is the proportionality constant.
Now, we shall substitute the given values of y and v in equation (1),
x = (3.0×10⁸ m/s) ÷ (3.0×10⁹ Hz)
or, x = 0.1 m
Hence, the required wavelength of the radio wave will be 0.1 m.