Two monochromatic rays of light are incident normally on the face AB of an isosceles right angled prism ABC. The refractive indices of the glass prism for the two rays '1' and '2' are respectively 1.35 and 1.45. Trace the path of these rays after entering through the prism.

Explanation

The critical angle for ray 1 is
`n=(1)/(sinc_(1))`
`sin c_(1)=(1)/(1.35)=0.741`
`"Therefore, "c_(1)=47.8^(@)`
`n=(1)/(sin c_(2)) or sin c_(2)=(1)/(1.45)`
`=0.6896`

The two rays will fall at an angle of incidence `45^(@)` at the face AC.
For ray .2. the angle of incidence is greater than the critical angle `43.6^(@)`. Hence it suffers total internal reflection, while ray .1. doen not. Hence the path of rays is as shown in the figure.