Consider the following statements.
Statement A: When light travels from a rarer to a denser medium, it loses speed.
Statement B: When light travels from a rarer to a denser medium, it loses energy.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → A is true but B is false.
Statement A: When light travels from a rarer to a denser medium, it loses speed. — True. The speed of light in a medium is \( v=c/n \), so it is smaller in the denser medium of larger refractive index. On refraction into a denser medium the speed and the wavelength decrease, while the frequency stays the same.
Statement B: When light travels from a rarer to a denser medium, it loses energy. — False. The energy carried by a wave depends on its amplitude. It does not depend on the speed of propagation. So the fall in speed does not mean a fall in the energy of the light.
NCERT (2026-27):
Example 10.1
