Condition for grazing emergence
Condition for grazing emergence :- For grazing emergence, i2 = 90°, we can determine the angle of incidence i1 for such grazing emergence.
As for a prism,
Applying Snell’s Law at interface AB, we get
Note :- The light ray will emerge out of the prism only if the angle of incidence i1 is greater than the above value.(This is because as A = i1 + i2 , so if i1 increases than i2 decreases and hence i2 < 90°)