1.8 g hydrogen atoms are excited to raditions . They study of spectra indicates that 27% of the atoms are
in 3rd energy level and 15% of atom in 2nd energy level and the rest in ground state .If .I.P.of H is
`21.7xx10^(-8)`erg . Calcute-
(i) No. the atoms present in III & II energy level .
(ii) Total energy evolved when all the atoms when all the atoms return to ground state.

Answer

`292.68xx10^(21)"atoms",162.60xx10^(21)"atoms",832.50KJ`

Explanation

No .of atoms in III level `=(27)/(100)xx((1.8)/(1))xxN_(A)=2.29xx10^(23)`atoms
No. of atoms in II level `=(15)/(100)xx((1.8)/(1))xxN_(A)=1.62xx10^(23)` atoms
Total energy `=2.92xx10^(23)xx2.18xx10^(-18)xx((1)/(1^(2))-(1)/(3^(2)))`
`+1.62xx10^(23)xx2.18xx10^(-18)xx((1)/(1^(2))-(1)/(3^(3)))=832.5 KJ`