Answer:
a) 3.3 m b) 283 m
Step-by-step explanation:
a) As radio waves are just another representation of electromagnetic waves, at some distance of the antenna, they behave like plane waves, and keep constant the following relationship between frequency, wavelength and wave speed:
λ*f = v
For an electromagnetic wave, v is just the light speed in the medium where the wave is propagating, which for clear air can be approximated by the value of the speed of light in vacuum, c, as follows:
c= 3*10⁸ m/s
⇒ λ = c/f = 3*10⁸ m/s / 91.5*10⁶ Hz = 3.3 m
b) As radio waves in the AM range behave exactly like ones in the FM range (at a distance from antenna larger than a few wavelengths) , same considerations apply, so we can find the wavelength λ using the same equation as above, for the 1060 Khz frequency:
⇒ λ = c/f = 3*10⁸ m/s / 1060*10³ Hz = 283 m.