Question

As the ray of light passes from air to glass, state how the wavelength of light changes. Does it increase, decrease or remain constant?

Answer 1

When light passes from air into glass, its speed decreases but its frequency remains constant. Since

\[ v = f\lambda \]

a decrease in speed v causes the wavelength λ to decrease.

\[{\lambda_{\text{glass}}<\lambda_{\text{air}}} \]

∴ Wavelength decreases in glass.