Question

The refractive index of glass is 1.5 form light waves of $\lambda = 6000Å$ in vacuum. Its wavelength in galss is :

• A. 2000 Å
• B. 4000 Å
• C. 1000 Å
• D. 3000 Å

Answer 1

Answer: (B)

4000 Å

Answer 2

: $\mu = \frac{c}{v} = \frac{v\lambda_{v}}{v\lambda_{g}}$

$\therefore\lambda_{g} = \frac{\lambda_{v}}{\mu} = \frac{6000}{1.5} = 4000Å$