Please solve 21 Ans.
n = FJh'V.
We have, E = nh•v,
6624 x 10-3
= 1022 approx.
or n = 6-62 x 10-34 X 1012
20. Calculate the frequency of a photon whose energy is 75 eV.
Ans. 18-2 x Hz.
21. Find out the energy of a photon whose (a) wavelength is 9-6A;
(b) wavelength is 6000A; and (c) frequency is 2000 kilocycles.
Ans. (a) 3-3 x 10-15 joule, (b) 3-3 x 10-19 joule, (c) 13•24 x 10-3
