Atoms & Nuclei

JEE Main level, single correct, medium

86 of 239

Question 86 of 239

In the Bohr model an electron moves in a circular orbit around the proton. Considering the orbiting electron to be a circular current loop, the magnetic moment of the hydrogen atom, when the electron is in nth n^{\text {th }} excited state, is :

Show answer and solution

Answer: (C) (e2m)nh2π\left(\frac{e}{2 m}\right) \frac{n h}{2 \pi}

Magnetic moment of the hydrogen atom, when the electron is in nth \mathrm{n}^{\text {th }} excited state, i.e., n′=(n+1)n^{\prime}=(n+1)
As magnetic moment
Mn=InA=in(πrn2)\mathrm{M}_{\mathrm{n}}=\mathrm{I}_{\mathrm{n}} \mathrm{A}=\mathrm{i}_{\mathrm{n}}\left(\pi \mathrm{r}_{\mathrm{n}}^2\right)
$\begin{aligned}

& i_n=e V_n=\frac{m z^2 e^5}{4 \varepsilon_0^2 n^3 h^3} \\

& r_n=\frac{n^2 h^2}{4 \pi^2 k z m e^2}\left(k=\frac{1}{4 \pi \epsilon_0}\right)

\end{aligned}$

Solving we get magnetic moment of the hydrogen atom for
nth \mathrm{n}^{\text {th }} excited state
Mn′=(e2m)nh2πM_{n^{\prime}}=\left(\frac{e}{2 m}\right) \frac{n h}{2 \pi}

JEE Main question paper PDF

Open a shift to read the full paper on this page, or download it.

JEE Main 2025 Apr 2 Shift 1 question paper

Open Download PDF

Opening paper…

Explain it as a whiteboard videoStep-by-step, in Hinglish or English. Your first video needs no login.Solved it on paper but got it wrong?Upload a photo of your working. Mistake Doctor marks the exact line that broke.
See it move: Atoms: Rutherford, Bohr and X-rays simulationDrag the sliders and watch the numbers in this question change.Revise Modern Physics firstFormula sheet, solved examples and the traps students fall into.

More Physics practice

JEE Main Physics practice question on Atoms & Nuclei (Bohr's Atomic Model), with the answer and a step-by-step solution. Scan a question from your own book or paper to get a whiteboard video.