A student sketches a ray diagram for a light beam passing from crown glass into air
PHYSICS · Multi-part · CBSE · Physics · Ray Optics and Optical Instruments · Ray Optics and Optical Instruments
Problem
A student sketches a ray diagram for a light beam passing from crown glass into air. The student draws the incident ray making a 40° angle with the normal inside the glass and then shows the refracted ray in air bending toward the normal at the interface.
Critically analyze the student’s diagram and respond to the prompts below.
(a) Identify the conceptual mistake in the student’s depiction of the refracted ray. State whether the refracted ray should bend toward or away from the normal when light travels from crown glass into air.
(b) Explain the physical reasoning behind your answer in part (a) by discussing the relative speeds of light in the two media and how that relates to their indices of refraction.
(c) The student claims that if the incident angle inside the glass were increased to 60°, the ray would still exit into the air but would bend even more toward the normal. Evaluate this claim. If the claim is incorrect, describe qualitatively what actually happens to the beam at larger incident angles in this situation.