question_answer

Radius of first Bohr orbit is r. What is the radius of 2nd Bohr orbit?

A) 8r                                           

B)        2r                           

C)        4r                                           

D)        \[2\sqrt{2}r\]

Correct Answer: C

Solution :

Radius of Bohr orbit \[r\propto {{n}^{2}}\] \[\frac{{{r}_{1}}}{{{r}_{2}}}={{\left( \frac{{{n}_{1}}}{{{n}_{2}}} \right)}^{2}}\] \[\Rightarrow \]               \[\frac{r}{{{r}_{2}}}={{\left( \frac{1}{2} \right)}^{2}}\] \[\Rightarrow \]               \[\frac{r}{{{r}_{2}}}=\frac{1}{4}\]       \[\Rightarrow \]               \[{{r}_{2}}=4r.\]