Mahesh Godavarti

Notice that the critical angle is the angle of incidence at which the angle of exit is equal to 90 \degree . If the angle of incidence exceeds the critical angle the light no longer exits the denser medium and the light undergoes total internal reflection.

Therefore, solve for 2.2 \times \sin \theta = 1.0 \times \sin 90^\degree .

Solve for \theta .

You should get \theta \approx 27 \degree .

Shubhanan Kulkarni
I understand. Thank you so much!