# When a beam of light with wave length $\lambda= 6000 A,$ travelling in air, enters a glass medium whose refractive index is 1.5 then,

(a)frequency of light remains constant

(b)velocity of light increase by 1.5 times

(c)frequency of light increase by 1.5 times

(d)wavelength $(\lambda)$ of light decreases by 1.5 times

When a beam of light enters from one medium to other, its frequency remains unchanged.
$v= n \lambda$ and $\mu =\large\frac{c}{v}$
$1.5 = n \large\frac{\lambda_1}{n \lambda_2}$
or $1.5=\large\frac{\lambda_1}{\lambda_2}$ or $\lambda_2=\large\frac{\lambda_1}{1.5}$
Hence wavelength decreases by 1.5 times.
Hence a and d are the correct answers.

edited Jul 23, 2014