Question

13. What is the maximum number of emission lines
obtained when the excited electron of a hydrogen
atom in n = 5 drops to ground state?
[NCERT Pg. 45]
(1) 5
(2) 10
(3) 15
(4) 8​

Answer 1

Explanation:

answer is 10 according to equation n(n-1)/2

Answer 2

Explanation:

When the excited electron of an H atom in n = 5 drops to the ground state,

the following transitions are possible:

The number of spectral lines: n(n−1)/2

where n=5

Hence the total number of spectral line will be: 2

5(5-1)/2

5×4/2

=10

Answer: Option-(2)