Question

Speed of electromagnetic waves is the same
(a) for all wavelengths
(b) in all media
(c) for all intensities
(d) for all frequencies

Answer 1

(c) for all intensities

For any given medium, the speed (c) of an electromagnetic wave is given by
c = νλ,
where
ν = ​frequency of the electromagnetic wave
λ = ​wavelength of the electromagnetic wave

As the frequency and wavelength are changed, the speed of the electromagnetic wave changes. So, the speed of an electromagnetic wave is not same for ​all wavelengths and​ all frequencies in any medium. The velocity of an electromagnetic wave changes with change in medium. Also, the speed of an electromagnetic wave is same for all the intensities in any medium.