A ray of light is incident on the upper face of a glass block at an angle of $15^\circ$ as illustrated. The refractive index of glass is $1.5$. What is the refraction angle $r$?
- A$10^\circ$
- B$23^\circ$
- C$40^\circ$
- D$50^\circ$
Physics 5054 · O Level · Refraction of light