Magnetic field at the centre of the hydrogen atom due to motion of electron in $\mathrm{n}^{\text {th }}$…
Magnetic field at the centre of the hydrogen atom due to motion of electron in $\mathrm{n}^{\text {th }}$ orbit is proportional to
- $\mathrm{n}^4$
- $\mathrm{n}^{-3}$
- $\mathrm{n}^3$
- $\mathrm{n}^{-5}$
Solution
The radius of the $\mathrm{n}^{\text {th }}$ Bohr orbit is, $r_n \propto n^2$.
The angular velocity of the electron, $\omega_n \propto \frac{1}{n^3}$
Also, current $I_n=\frac{q}{T_n}=\frac{q \omega_n}{2 \pi}$
$\begin{array}{ll}
\therefore \quad & \mathrm{I}_{\mathrm{n}} \propto \omega_{\mathrm{n}} \propto \frac{1}{\mathrm{n}^3} \\
& \text { Now, } \mathrm{B}_{\mathrm{n}}=\frac{\mu_0 \mathrm{I}_{\mathrm{n}}}{2 \mathrm{r}_{\mathrm{n}}} \\
\therefore \quad & \mathrm{B}_{\mathrm{n}} \propto \frac{1}{\mathrm{n}^3} \times \frac{1}{\mathrm{n}^2} \\
\therefore \quad & \mathrm{B}_{\mathrm{n}} \propto \frac{1}{\mathrm{n}^5}
\end{array}$
Asked in: MHT CET 2023 (14 May Shift 1)
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