Dispersion: Light consisting of a mixture of red and blue light enters a 40°, 70°, 70° prism along a line parallel to the side opposite the 40° vertex. The index of refraction of the prism material for blue light is 1.530, and for red light it is 1.525. What is the angle between the two emerging beams of light?

Question

Quizplus · Accepted Answer

The angle of incidence is 90°-70°=20°
Using Snell's law: 
sin(20°)/1.530 = sin(theta_blue)/sin(40°)
sin(20°)/1.525 = sin(theta_red)/sin(40°)

Solving for theta_blue and theta_red, we get:
theta_blue = 24.57°
theta_red = 24.87°

The angle between the two emerging beams of light is:
theta_blue - theta_red = -0.3°
Therefore, the answer is D.

Dispersion: Light Consisting of a Mixture of Red and Blue