Question

Explain the following, giving reasons:
(i) when monochromatic light is incient incident on the surface seperating two media, the reflected and refracted light both have the same frequency as the incident frequency.
(ii) when light travels from rarer to denser medium, speed decreases. does the decrease in speed imply reduction in the energy carried by the wave?
(iii) in the wave picture of light, intensity if light is determined by the square of the amplitude of the wave. what determines the intensity in the photon picture of light?

Answer 1

(i) The frequency of reflected and refracted light remains same as that of incident light because frequency only depends on the source of light.
(ii) Since the frequency remains same, hence there is no reduction in energy.
(iii)In the wave picture of light, the intensity of light at a pt. is determined by the no. of photons incident per unit area around that point.