A narrow beam of light approaches a flat water surface from air
PHYSICS · Multi-part · CBSE · Physics · Light — Reflection and Refraction · Light — Reflection and Refraction
Problem
A narrow beam of light approaches a flat water surface from air. The angle of incidence in air is gradually varied from 0° to 90°.
Respond to the following prompts about the beam’s behavior at the water surface.
(a) Describe the path of the refracted beam when the angle of incidence is exactly 0° (along the normal). Explain why no change in direction is observed.
(b) Describe qualitatively how the refracted beam’s direction changes as the incident angle in air increases from 0° toward 90°. Indicate whether it bends toward or away from the normal and how the amount of bending evolves.
(c) In the limiting case as the incident angle approaches 90° (grazing incidence), predict the approximate direction of the refracted beam inside the water relative to the surface. Explain how this limiting behavior is consistent with your description in part (b).