Atoms and Nuclei Part 1

We have no find the frequency of emitted photons. For emission of photons the transition must take place from a higher energy level to a lower energy level which are given only in options (c) and (d)
Frequency is given by
hv=−13.6(‌

1

n22

−‌

1

n12

)
For transition from n=6 to n=2,
v1=‌

−13.6

h

(‌

1

62

−‌

1

22

)
=‌

2

9

×(‌

13.6

h

)
For transition from n=2 to n=1,
v2=‌

−13.6

h

(‌

1

22

−‌

1

12

)
=‌

3

4

×(‌

13.6

h

)
∴v1>v2