A student carries out the experiment of tracing the path of a ray of light through a rectangular glass slab, for two different values of angle of incidence ∠ i = 30 ° and ∠ i = 45 ° . Find the set of values of the angle of refraction ( ∠ r) and the angle of emergence ( ∠ e), she is likely to observe in the two cases.

Question

Philoid · Accepted Answer

For light going from air to glass at point E

μ_a sin i = μ_g sin r ……. (1)

For light going from glass to air at point F

μ_g sin r = μ_a sin e ……. (2)

From (1) and (2) we can say that i = e

Case 1. When ∠i = 30^o

μ_a sin i = μ_g sin r

Sin r = 1/3

r = 19.26^o

And i = e

So e = 30^o

Case 2. When ∠i = 45^o

μ_a sin i = μ_g sin r

1×sin45 = 3/2×sin r

1/√2 = 3/2×sin r

Sin r = √2/3

r = 28.09^o

And i = e

So e = 45^o