Answer:
The angle of incidence is 39 degrees
Step-by-step explanation:
We would apply Snell's law which states that the ratio of the angle of incidence to the sine of the angle of refraction is constant. It is expressed as
n1Sinθ1 = n2Sinθ2
Sinθ1/Sinθ2 = n2/n1
where
θ1 is the angle of incidence
θ2 is the angle of refraction
n1 is the refractive index of air
n2 is the refractive index of glass
From the information given,
n1 = 1.6
θ2 = 90
n2 = 1
Thus,
1.6 x Sinθ1 = 1 x Sin90
Sinθ1 = 1Sin90/1.6 = 0.625
θ1 = Sin^-1(0.625)
θ1 = 39 degrees