Electronic transition in He ion takes from n_2 to n_1 shell such that :2n_2 + 3n_1 = 18 , 2n_2 - 3n_1 = 6 What will be the total number of photons emitted when electrons transit to n_1 shell ?

Electronic transition in He ion takes from n_2 to n_1 shell such that

1.	Electronic transition in He ion takes from n_2 to n_1 shell such that :2n_2 + 3n_1 = 18 , 2n_2 - 3n_1 = 6 What will be the total number of photons emitted when electrons transit to n_1 shell ?
Answer» 21 15 20 10 Solution :`4n_2 = 24 impliesn_2 = 6` `n_1 = 2 ` no. of spectral lines `(4(5))/(2)` = 10