NEET Chemistry Structure of Atom / परमाणु संरचना NEET PYQ-Structure of Atom

According to the Bohr theory, which of the following transitions in the hydrogen atom will give rise to the least energetic photon?                                                                                                                        [AIPMT (M) 2011]

A) \[n=6\] to \[n=1\]

B)      \[n=5\] to \[n=4\]

C) \[n=6\] to \[n=5\]

D) \[n=5\] to \[n=3\]

Correct Answer: C

Solution :
\[\because \Delta E\propto \left[ \frac{1}{n_{1}^{2}}-\frac{1}{n_{2}^{2}} \right],\] where \[{{n}_{2}}>{{n}_{1}}\]

Energy of photon obtained from the transition \[n=6\] to \[n=5\] will have least energy.