A short bar magnet is placed in the magnetic meridian of the earth with north pole pointing north. Neutral points are found at a distance of 30 cm from the magnet on the East – West line, drawn through the middle point of the magnet. The magnetic moment of the magnet in Am2 is close to: (Given 0 4 m p = 10–7 in SI units and BH=Horizontal component of earth’s magnetic field = 3.6 × 10–5 tesla)

Question:

A short bar magnet is placed in the magnetic meridian of the earth with north pole pointing north. Neutral points are found at a distance of $30 \mathrm{~cm}$ from the magnet on the East – West line, drawn through the middle point of the magnet. The magnetic moment of the magnet in

$\mathrm{Am}^{2}$ is close to: (Given $\frac{\mu_{0}}{4 \pi}=10^{-7}$ in SI units and $\mathrm{B}_{\mathrm{H}}$$=$ Horizontal component of earth’s magnetic field $=3.6$ $\times 10^{-5}$ tesla)

  1. $14.6$

  2. $19.4$

  3. $9.7$

  4. $4.9


Correct Option: 3

JEE Main Previous Year 1 Question of JEE Main from Physics Magnetism and Matter chapter.
JEE Main Previous Year Online April 11, 2015

Solution:

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