The ratio of the radius of the first Bohr orbit to that of the second Bohr orbit of the orbital electron is
The ratio of the radius of the first Bohr orbit to that of the second Bohr orbit of the orbital electron is
$4: 1$
$2: 1$
$1: 4$
$1: 2$
Solution
Radius of $\mathrm{n}^{\text {th }}$ Bohr orbit, $\mathrm{r}_{\mathrm{n}}=\mathrm{n}^2 \mathrm{r}_0$ Ratio of first Bohr orbit to second Bohr orbit,
$\begin{aligned}
& \frac{\mathrm{r}_1}{\mathrm{r}_2}=\left(\frac{1}{2}\right)^2 \times \frac{\mathrm{r}_0}{\mathrm{r}_0} \\
& \therefore \quad \frac{r_1}{r_2}=\frac{1}{4}
\end{aligned}$
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