The number of spectral lines that are possible when electrons in the shell of different hydrogen atoms return to the shell is:
Explanation for the correct option:
[B]
So, option [B] is correct.
Explanation for the Incorrect options:
[A]
So, option[A] is incorrect.
[C]
So, option[C] is incorrect.
[D]
So, option[D] is incorrect.
Hence, option[B] is the no. of spectral lines possible.