Answer to Question #214399 in Electricity and Magnetism for John Mark

Question

Light travelling in air strikes a flat piece of uniformly thick glass at an incident angle of 60.0°, as shown. If the index of refraction of the glass is 1.50, (a) what is the angle of refraction θA in the glass; (b) what is the angle θB at which the ray emerges from the glass?

Answer 1

According to Snell's Law

$n_1sin \theta_1= n_2sin \theta_2$

a) When ray strikes the thick mirror

$n_1=1 \\ n_2=1.5 \\ \theta_1=60^o \\ \theta_2=\theta_A \\ 1 \times sin60 =1.5 \times sin \theta_A \\ \theta_A =35.26^o$

b) when the light emerges out from thick mirror

$n_1=1.5 \\ n_2=1 \\ \theta_1=35.26^o \\ \theta_2=\theta_B \\ 1.5 \times sin 35.26=1 \times sin \theta_B \\ \theta_B= 60^o$