Question

Roberto was testing how light interacted with a material he had just developed. The initial speed of light was
3.0 × 108 m/s. The final speed of light after it changed direction was 1.7 × 108 m/s.

What type of interaction took place?

Answer 1

That is refraction. When light enters a medium it can change direction and slow down. The refractive index n = c/v = (3.0×10^8 m/s)/(1.7×10^8 m/s) ≈ 1.76, so the light bent and slowed on entering a material with n ≈ 1.76.