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Q20
(CISF/2019)
Science & Technology › Basic Science (Physics, Chemistry, Biology)
The horizontal component of the earth's magnetic field is zero at
Explanation
The Earth's magnetic field at any location can be resolved into a horizontal component (BH) and a vertical component (BV). This is determined by the angle of dip (θ), which is the angle that the total magnetic field vector makes with the horizontal surface.
The horizontal component is calculated as: BH = B cos θ.
- At the magnetic equator, the magnetic field lines are parallel to the Earth's surface, meaning the angle of dip is 0°. Thus, BH = B cos 0° = B (maximum).
- At the magnetic poles, the magnetic field lines are perpendicular to the Earth's surface, meaning the angle of dip is 90°. Since cos 90° = 0, the horizontal component BH becomes zero.
Option C is incorrect because geographic poles do not exactly coincide with magnetic poles, where this specific physical phenomenon occurs.
✓ Thank you! We'll review this.