Physics-Bar Magnet
NEET Physics Bar Magnet MCQ Question
Type: MCQ-numerical-Easy-Class 12
A bar magnet is placed in a horizontal plane with its axis along the magnetic north-south direction. If null points are found 14 cm from the center of the magnet, what is the magnetic dipole moment of the magnet? Assume the horizontal component of the earth's magnetic field is 0.36 G.
A
0.056 Am²
B
0.072 Am²
C
0.084 Am²
D
0.092 Am²
Correct Answer
Option A
Detailed Explanation
At null points, the magnetic field due to the magnet is equal and opposite to the horizontal component of the earth's magnetic field. Using the formula for the magnetic field on the axial line of a bar magnet, B = (μ₀/4π) * (2M/d³), and equating it to 0.36 G, the magnetic moment M is found to be 0.056 Am².
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