Write three characteristic features in the photoelectric effect which cannot be explained on the basis of the wave theory of light but can be explained only using Einstein's equation.
Answer: Threshold frequency; (not intensity); no time lag.
Solution
(1) Threshold frequency: there is a minimum frequency below which no emission occurs, however intense the light — wave theory predicts emission at any frequency if intensity is large enough.
(2) ** independent of intensity:** the maximum kinetic energy depends only on frequency (), not on intensity — wave theory predicts should grow with intensity.
(3) No time lag: emission is practically instantaneous — wave theory predicts a measurable delay while energy accumulates.
(2) ** independent of intensity:** the maximum kinetic energy depends only on frequency (), not on intensity — wave theory predicts should grow with intensity.
(3) No time lag: emission is practically instantaneous — wave theory predicts a measurable delay while energy accumulates.
CBSE Class 12 Board · 2016 · Delhi · Subjective