Question

The ratio of area covered by second orbital to the first orbital is :

• A. 1 : 2
• B. 1 : 16
• C. 8 : 1
• D. 16 : 1

Answer 1

Answer: (D)

According to Bohr
$r_n\propto \frac{n^2}{Z}\left[r=\frac{0.529n^2}{Z}\mathring{A}\right]$
$\frac{r_2}{r_1}=\frac{(2{)}^2}{(1{)}^2}=\frac{4}{1}$
Area $=\pi r^2$
$\Rightarrow \frac{A_2}{A_1}=\frac{\pi r_2^2}{\pi r_1^2}={\left(\frac{r_2}{r_1}\right)}^2={\left(\frac{4}{1}\right)}^2=\frac{16}{1}$