A positronium atom consist of an electron and a positron revolving about their common centre of mass . Calculate
Separation between the electron and positron in their first excited state.

Options

A. `4.232Å`
B. `5.232Å`
C. `6.2Å`
D. `7.Å`

Answer

A

Explanation

`(Ke^(2))/r^(2)=mw^(2)`…..(1)

` L=m(omegar/2)r/2xx2=(nh)/(2pi)`….(2)
` ((n^(2)h^(2))/(hpi^(2)mKe)^(2))xx2=(0.529Å)xx2n^(2)`
For first excited state `n=2`
` r=8xx0.529Å`, r=4.232Å