(i) Monochromatic light of frequency 6.0 \times 10^{14} {\Hz} is produced by a laser. The power emitted is 2.0 \times 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.

CBSE Class 12 Physics 2014 Delhi Set 1 Paper

Question : 18

Total: 30

(i) Monochromatic light of frequency 6.0×1014‌Hz is produced by a laser. The power emitted is 2.0× 10−3W. 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) An energy,
E‌=hv
‌=6.63×10−34×6.05×1014
‌=3.98×10−19J
Now,number of photons emitted per second
n‌=‌

=2.0×‌

10−3

3.98

×10−19J
‌=5×1015‌ photons per second ‌
(ii)

Go to Question:

Prev Question

Next Question