Question

If a ray of light passes from a denser medium to a rarer medium in a straight line, the angle of incidence must be ................

• A. \( 0^\circ \)
• B. \( 30^\circ \)
• C. \( 60^\circ \)
• D. \( 90^\circ \)

Hint:

For light to pass through the boundary between two media without bending, the angle of incidence must be \( 0^\circ \), i.e., the ray must be perpendicular to the surface.

Answer 1

The Correct Option is A

When a ray of light passes from a denser medium (like water or glass) to a rarer medium (like air), if it travels in a straight line without bending, it must be incident at \( 0^\circ \), meaning the ray is parallel to the normal. This is because refraction occurs only when the light ray strikes the interface at an angle other than \( 0^\circ \).