Question

An electron makes transition from $n=3,n=1$ state in a hydrogen atom. The different possible number of photons that can be emitted is :

• A. $1$
• B. $2$
• C. $3$
• D. $6$

Answer 1

The correct option is C $3$

For transition from $n=3$ to $n=1$
Possible number of photons $={}^3{C}_2$$=\frac{3!}{(3-2)!2!}$$=\frac{3\times 2\times 1}{1\times 2\times 1}=3$