Question

For 589-nm light, calculate the critical angle for the following materials surrounded by air. (a) fluorite (n = 1.434) ° (b) crown glass (n = 1.52) ° (c) ice (n = 1.309)

Answer 1

Answer:

a) θc = 44.21⁰.

b) θc = 41.14⁰

c)  θc = 40.36⁰

Explanation:

sin θ = $\dfrac{n_2}{n_1}$

For air,

n₂ = 1

so,

sin θ =  $\dfrac{1}{n_1}$

(a) fluorite : n₁ = 1.434⁰

sin θ = 0.697                   θc = 44.21⁰.

(b) crown glass: n₁ = 1.52⁰  

sin θ = 0.657                   θc = 41.14⁰.

(c) sodium chloride : n₁= 1.544⁰

sin θ = 0.647                   θc = 40.36⁰.