Refraction and Lenses Practice Test

In Snell's law, theta2 is the angle the light ray makes with the normal inside the second medium after crossing the boundary. It tells you how the ray bends when it enters a new material, and Snell's law relates it to theta1, the angle the incident ray makes with the normal in the first medium, via n1 sin(theta1) = n2 sin(theta2). The angle of reflection is a separate concept: it’s the angle the ray would form if it simply reflects off the interface, and it does not appear in Snell's law. The angle of critical is a special case where theta2 becomes 90 degrees, marking the onset of total internal reflection. So theta2 specifically denotes the angle of refraction.