Question

The refractive index of glass is $1.5$ for light waves of $\lambda =6000\mathring{A}$ in vacuum. Its wavelength in glass is

• A. $2000\mathring{A}$
• B. $4000\mathring{A}$
• C. $1000\mathring{A}$
• D. $3000\mathring{A}$

Answer 1

Answer: (B)

$\mu =\frac{c}{v}=\frac{{\lambda }_v}{{\lambda }_g}$
$\therefore {\lambda }_g=\frac{{\lambda }_v}{\mu }$
$=\frac{6000}{1.5}=4000\mathring{A}$