Question

Calculate the refractive index of the medium Y, when a light ray enters from air at an angle, i = ${45}^0$ and and refracts at an angle, r = ${30}^0.$

• A.
  0.7
• B.
  1.41
• C.
  2.8
• D.
  3

Answer 1

The correct option is B

1.41
Angle of incidence = ${45}^0$
Angle of refraction = ${30}^0$
Incident medium is air.
Refractive index of air = 1
Let the refractive index of the medium Y be $\eta$
Then using Snell's Law,
${\eta }_{air}\sin i={\eta }_Y\sin r{\eta }_Y=1\times \frac{\sin i}{\sin r}{\eta }_Y=\frac{\sin {45}^0}{\sin {30}^0}{\eta }_Y=\sqrt{2}=1.41$