Question

When a wave moves from one medium to another medium frequency remains same. What law is this?

Answer 1

➡Light is refracted when it crosses the interface from air into glass in which it moves more slowly.
➡Since the light speed changes at the interface, the wavelength of the light must change, too.
➡ The wavelength decreases as the light enters the medium and the light wave changes direction.
➡The frequency, wavelength, and speed are related by:

➡Velocity = wavelength x frequency