`A` vessel contains `X` moles of `H(g)` at P atm `&` T.K. If radiation is used to excite these H-atoms from ground state to nth excited state find total energy (in joules) required in form of radiations?

Explanation

Total no. of H-atoms in sample `=XN_(A)`
Energy required for transition `[1rarr(n+1)]` per H-atom `=-13.6eV[(1)/((n+1)^(2))-1]`
`=13.6[1-(1)/((n+1)^(2))] eV//"atom"`
Total energy required for `'XN'_(A)` atoms
`=13.6[1-(1)/((n+1)^(2))] (XN_(A))eV`
`13.6[1-(1)/((n+1)^(2))](XN_(A))xx1.6xx10^(-19)` Joules