Question

A light passing through air has wavelength $\lambda =600nm$. Wavelength, when same ray passes through a glass slab of refractive index 1.5 is:

• A. $4000$ $A^{\circ }$
• B. $2000A^{\circ }$
• C. $8000$ $A^{\circ }$
• D. $1200$ $A^{\circ }$

Answer 1

The correct option is A $4000$ $A^{\circ }$

We have
$\frac{\mu }{{\mu }^{\prime }}=\frac{{\lambda }^{\prime }}{\lambda }$
where, $\lambda$ and ${\lambda }^{\prime }$ respectively are the wavelength of the light in air and in glass slab.
$\mu$ and ${\mu }^{\prime }$ is the refractive index of air and glass slab respectively.
We have $\mu =1$ and ${\mu }^{\prime }=1.5$
$⟹{\lambda }^{\prime }=\frac{600nm}{1.5}=400nm=4000A^o$