Question

When light enters glass from vacuum, then the wavelength of llght ______.

Options

• decreases

• becomes zero

• remains same

• increases

Answer 1

When light enters glass from vacuum, then the wavelength of llght decreases.

Explanation:

When light enters glass from a vacuum, then the wavelength of light decreases. This is because the speed of light in glass is less than that in the vacuum.

From Snell's law, the refractive index in a medium is given by

`mu = "c"/"v"`

The glass is of higher refractive index than vacuum, so speed of light decreases and as the speed of light is directly proportional to the wavelength (c = vλ), so, the wavelength also be decreased.