A ray of light traveling in air strikes the surface of a liquid.

Question

If the angle of incidence is 33.5◦
and the
angle of refraction is 19.8◦, find the critical
angle for light traveling from the liquid back
into the air.
Answer in units of◦

Answer 1

find n.

sin33.5=n*sin19.8

then, critical angle= arcsin n

Answer 2

do I put my calculator in degrees?

Answer 3

yes, I would.

Answer 4

I keep getting error

Answer 5

sinr1/sinr2 = n2/n1,
n1 = 1.003 (for air)
n2 = n1•( sinr1/sinr2) = 1.6244
sinr(o) = 1/n2 = 0.6156
r(o) – arcsin(0.6156) = 38 degr.