8.37) An electron in the first excited state of hydrogen is struck by a photon of light of
wavelength 656.48 nm. a) What is the frequency of the photon? b) What is the energy of this
photon? c) To which energy level did the electron go?
Solution
(a)
Frequency = speed of light / wave length = 3 * 10 8
/ ( 656.48 * 10 -9
) = 4.57 * 10 14
Hz
(b)
Energy = Planck's constant * frequnecy
E = 6.626 * 10 -34
* 4.57 * 10 14
= 3.03 * 10 -19
J
(c)
Energy = 2.18 * 10 -18
/ n 2
J
n 2
= 2.18 * 10 -18
/ ( 3.03 * 10 -19
)
n = 2.68
Hope it will enter into 3rd energy level i.e 2nd excited state.