When leaving a fish tank, a ray moving at 31.0 deg in glass (n = 1.50) exits into the air. At what angle does it enter the air?

Answer: 20 degrees

Explanation:

Given that the

Refractive index n = 1.5

Incident angle = 31 degree

The refractive index formula is:

n = sin I/sin R

1.5 = sin 31 / sin R

Make sin R the subject of formula

Sin R = sin 31 / 1.5

Sin R = 0.515 / 1.5

Sin R = 0.343

R = sin^-1 (0.34335)

R = 20 degrees

Therefore, it enters the air at angle 20 degrees