The refractive index of diamond is 2.42. A ray of light passing from the inside of a diamond into air makes an angle of incidence of 20 degrees. Find the angle of refraction.
n = refractive index
aNd = 2.42 (my book said the speed of light in a vacuum and in air are close enough to treat them as the same for our purposes)
dNa = 1/aNd
Sin i / Sin r = dNa
i = 20 degrees
The Attempt at a Solution
0.413 = dNa
Sin 20 degrees = 0.3420
0.3420 / sin r = 0.413
therefore 0.3420 x 0.413 = sin r
sin r = 0.142
arc sin of 0.142 = 8.159 degrees
This is wrong, the answer should be 55.9 degrees..
Where did I go wrong?
Did I go wrong in my maths or in my use of the formula?
If someone could point me in the right direction that would be wonderful.