No, when the speed of light changes, the frequency and wavelength of light do not change. According to the fundamental relationship between frequency (f), wavelength (λ), and the speed of light (c):
c = f * λ
The equation shows that the speed of light is equal to the product of frequency and wavelength. If the speed of light were to change, the product of frequency and wavelength must remain constant for a given medium. In other words, if the speed of light decreases, the wavelength must decrease proportionally to maintain the same frequency, and if the speed of light increases, the wavelength must increase proportionally to maintain the same frequency.
This phenomenon is known as the index of refraction, which describes how light slows down or speeds up as it passes through different materials. The index of refraction affects the speed of light, but it does not change the frequency or wavelength of the light itself.