When light enters glass from vacuum then the wavelength of light
When light enters glass from vacuum then the wavelength of light
remains constant.
becomes zero.
decreases.
increases.
Solution
When a light enters glass form vacuum, then the wavelnght of light decrease.
This is because the speed of light in glass in less than that in the vacuum.
From Snell's law the refractive index in a medium is given by.
$\mu=\frac{c}{v}$
The glass is of higher refractive index than vaccum, so speed of light decrease and as teh speed of light is drectly proportional to the wavelenght ( $c \equiv v \lambda$ ), So the wavelenght also be decrease.