Question

Question 2.15 What is the maximum number of emission lines when the excited electron of an H atom in n = 6 drops to the ground state?

Class XI Structure of Atom Page 66

Answer 1

Number of lines produced when electron from nth shell drops to ground state = n(n-1)/2

Now according to question lines produced when electron drops from 6th shell to ground state

= 6(6-1) / 2 = 15

These are produced due to following transition

6 to 5      5 to 4    4 to 3     3to 2     2 to 1
(5 lines)

6 to 4     5 to 3    4 to 2     3 to 1             (4 lines)  

6 to 3     5 to 2    4 to 1                          (3 lines)

6 to 2     5 to 1                                      (2 lines)

6 to 1                                                    (1 lines)

Answer 2

maximum Number of emission lines produced when electron from nth shell drop to the ground state = n( n - 1 )/2

actual formula for finding number of spectral line is (n₂ -n₁)(n₂ -n₁ + 1)/2
where , electrons moves from n₁ state to n₂ state


here, excited electron of an H-atom in n = 6 drops to the ground state .
so, maximum number of emission lines = 6(6-1)/2 = 6 × 5/2 = 15