A hydrogen atom in its ground state absorbs 10.2 eV of energy. What is the increase in its orbital angular momentum ? S

Options

A. `2.11xx10^(-34)` J-sec
B. `3.16xx10^(-34)` J-sec
C. `1.05xx10^(-34)` J-sec
D. `4.22xx10^(-34)` J-sec

Answer

C

Explanation

The electron in the ground state (n=1) has energy =-13.6 eV. When it absorbs an energy 10.2 eV, its energy becomes -13.6 + 10.2 = -3.4
`therefore E_n = - (13.6)/(n^2) therefore n^2 = (13.6) /(3.4) = 4 therefore n=2`
It has gone from n=1 to n=2
`therefore` its orbital angular momnetum is increased by
`(2-1) (h)/(2pi) = (h) /( 2pi)`
`therefore " thus " (h)/(2pi) = (6.6xx10^(-34))/(6.28) = 1.05xx10^(-34) J-s`