Question

Behind the lens of the eye is the vitreous humor, a jellylike substance that occupies most of the eyeball. The refractive index of the vitreous humor is 1.32 and that of the lens is 1.47. A narrow beam of light traveling in the lens comes to the interface with the vitreous humor at a 23 ∘∘ angle with respect to the normal.

What is its direction relative to the interface when in the vitreous humor?

Express your answer in degrees.

Answer 1

Using Snell's law,
n1 * sini = n2 * sinr
Where n1 and n2 are the refractive indices of the lens and vitreous humor; i is the incident angle and r is the refracted angle with respect to the normal.
sinr = (n1 * sini) / n2
= (1.47 * sin(23)) / 1.32
= 0.435

r = sin-1(0.435)
= 25.8 degrees