Find the minimum and maximum deflectrion angls for a light ray passing through a glass prism with refracting angle `theta = 60^(@)`.

Explanation

In the case of minimum deviation
`sin.(alpha + theta)/(2) = n sin.(theta)/(2)`
So, `alpha = 2sin^(-1) {n sin .(theta)/(2)} - theta = 37^(@)`, for `n = 1.5`
Passage of ray for grazing incidence and grazing imergence is the condition for maximum (Fig.) From Fig.
`alpha = pi - theta = pi - 2theta_(cr)`
(where `theta_(cr)` is the critical angle)
So, `alpha = pi-2 sin (1//n) = 58^(@)`,
for `n = 1.5 = R.I.` of glass.