Class 12 NEET Physics Atoms and Nuclei Part 1

Ionisation potential of hydrogen atom is 13.6eV.
Energy required for exciting the hydrogen atom in the ground state to orbit n is given by
E=En−E1
i.e., 12.1=−

13.6

n2

−(

−13.6

12

) =−

13.6

n2

+13.6
or, −1.5=

−13.6

n2

or, n2=

13.6

1.5

=9 or, n=3
Number of spectral lines emitted
=

n(n−1)

2

=

3×2

2

=3