Question

A beam of light passing from air enters into the glass. Identify which of the following statements is true?

• A. The angle of incidence is greater than the angle of refraction in the glass.
• B. The angle of incidence is less than the angle of refraction in the glass.
• C. The angle of incidence is equal to the angle of refraction in the glass.
• D. The frequency of the light decreases.
• E. The frequency of the light increases.

Answer 1

The correct option is A The angle of incidence is greater than the angle of refraction in the glass.

Let the refractive index of air be ${\mu }_a$ and that of the glass be ${\mu }_g$.

Also let $i$ be the angle of incidence and $r$ be the angle of refraction.

From Snell's law,

${\mu }_a\sin i={\mu }_g\sin r\Rightarrow \frac{{\mu }_a}{{\mu }_g}=\frac{\sin r}{\sin i}$

As ${\mu }_g>{\mu }_a\Rightarrow \sin i>\sin r\Rightarrow i>r$

Therefore option A is correct.

The frequency of the light doesn't change during refraction because frequency is a property of the source of light.