question_answer

In Bohr's model, the atomic radius of the first orbit is \[{{r}_{0}},\]then the radius of the third orbit is

A) \[\frac{{{r}_{0}}}{9}\]                         

B) \[{{r}_{0}}\]

C)  \[9{{r}_{0}}\]                         

D)  \[3{{r}_{0}}\]