Question

Fill in the blanks :

A light ray travelling obliquely from a denser medium to a rarer medium bends ................... the normal. A light ray bends ................... the normal when it travels obliquely from a rarer to a denser medium.

Answer 1

When a light travels from denser to rarer medium it bends away from the normal. It can be verified by Snell's law . $\frac{n_i}{n_r}=\frac{sin{\theta }_r}{sin{\theta }_i}$

If $n_i>n_r$ then ${\theta }_i<{\theta }_r$. Light bends away from the normal when it travels from denser to rarer medium.

If $n_i<n_r$ then ${\theta }_i>{\theta }_r$. Light bends towards the normal when it travels from rarer to denser medium.

Answer:

(i) away from

(ii) towards