Question
(i) Monochromatic light of frequency 6.0 × 1014 Hz is produced by a laser. The power emitted is 2.0 × 10−3 W. Estimate the number of photons emitted per second on an average by the source.
(ii) Draw a plot showing the variation of photoelectric current versus the intensity of incident radiation on a given photosensitive surface.
Solution
i) Given,
Frequency of light,
Power emitted by light,
Number of photons emitted per second on an average is equal to Power per unit energy of one photon.
Energy of one photon is given by, Energy = hν.
Therefore,
Number of photons emitted per second =
= 
(ii) The plot below shows the variation of photoelectric current Vs. Intensity of incident radiation on a given photosensitive surface. The plot shows a linear proportion.
