Question

A monochromatic ray of light enters a glass slab $(n=1.5)$ along the normal to the surface. The angle of deviation of the refracted ray is:

• A. ${90}^0$
• B. ${45}^0$
• C. ${30}^0$
• D. $0^0$

Answer 1

Answer: (D)

$0^0$

Ray of light enters the glass slab normally.

Angle of incidence, $i=0^0$

Let the angle of refraction be $r$.

Using Snell's law:

$n_1\sin i=n_2\sin r$

$1\sin 0^0=n_2\sin r$

$\sin r=0^0$

$\Rightarrow r=0^0$

This means that the ray continues along its original path implying no deviation.