The refractive index of a material is 1.5. Calculate the critical angle at the glass-air interface
A
19o
B
21o
C
39o
D
42o
Verified Correct Answer: D.
Physical Principles & Numerical Solution
Sin C = \(\frac{1}{\eta} = \frac{1}{1.5} = 0.6667\)
C = sin\(^{-1}\) 0.6667
= 42^\circ
Source: Myschool Past Questions Archive (Record #35675)