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Difficulty: HardMagnetism and Earth's Magnetic Field

When a bar magnet is placed in the magnetic meridian with its North pole pointing towards the Earth's magnetic North pole, the neutral points formed where its magnetic field cancels the horizontal component of the Earth's magnetic field lie along its end-on (axial) line.

Answer: Answer

Answer

The statement is false. When a bar magnet is placed with its North pole pointing towards magnetic North, neutral points lie along its broadside-on (equatorial) axis, not its end-on (axial) axis.
The statement is incorrect. When a bar magnet's North pole points North, its magnetic field along its axis points in the same direction as Earth's horizontal field, reinforcing it. The fields oppose each other and form neutral points along the broadside-on (equatorial) line.

Step-by-Step Solution

1
Determine the direction of Earth's horizontal magnetic field
The horizontal component of Earth's magnetic field (BHB_H) points Northward along the magnetic meridian.
By definition, Earth's horizontal magnetic field vectors point from magnetic South to magnetic North.
2
Analyze the magnetic field of the bar magnet along its axial (end-on) line
Outside the magnet along its axis, field lines point away from the North pole (Northward).
Since both the magnet's field and Earth's horizontal field point Northward along the axial line, they reinforce each other (Btotal=Bmagnet+BH>0B_{\text{total}} = B_{\text{magnet}} + B_H > 0), so no neutral points can form here.
3
Analyze the magnetic field of the bar magnet along its equatorial (broadside-on) line
Along the equatorial line, field lines curve from the North pole to the South pole, pointing Southward.
Because the magnet's field points Southward while Earth's field points Northward, they oppose each other and cancel when equal in magnitude (Bmagnet=BHB_{\text{magnet}} = B_H).
4
Evaluate the statement
The neutral points form on the broadside-on (equatorial) line, making the given statement false.
The statement incorrectly asserts that neutral points occur on the end-on (axial) line.

Key Concept

Neutral points of a bar magnet in Earth's magnetic field
Estimated Time:2m 0s
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Topics

Magnetism and Earth's Magnetic Field

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