Magnetic pole interaction: When the north poles of two bar magnets are brought close together, what happens?
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Aa force of attraction
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Bno force
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Ca downward force
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Da force of repulsion
Answer
Correct Answer: a force of repulsion
Explanation
Introduction / Context:Basic magnetic interactions mirror electrostatic analogies: like poles repel and unlike poles attract. Recognizing these interactions is critical in designing magnetic couplings, holding fixtures, and understanding motor forces.
Given Data / Assumptions:
- Two bar magnets with clearly identified north poles.
- Magnets are brought close together in free space.
Concept / Approach:Field lines emerge from each north pole and seek to enter a south pole. When two north poles face each other, their field lines conflict, creating a region of high magnetic pressure and resulting in a repulsive mechanical force pushing the magnets apart.
Step-by-Step Solution:
Identify pole orientation: N facing N.Recall rule: like poles repel, unlike poles attract.Therefore, the mechanical interaction is repulsion.Verification / Alternative check:Hands-on demonstration with two bar magnets: attempt to push two north poles together and feel resistance. Field visualization with iron filings shows crowding and deflection, consistent with repulsive force lines.
Why Other Options Are Wrong:
- A force of attraction: Occurs only for N–S facing alignment.
- No force: Magnetic fields exert forces on magnetic dipoles; null only at very large separations.
- A downward force: Direction depends on how magnets are constrained; the fundamental interaction is repulsive, not direction-specific like “downward”.
Common Pitfalls:
- Confusing electric charge rules with magnetic poles but the rule is analogous: like repels, unlike attracts.
- Misinterpreting “downward” as a universal direction; magnetic forces act along the line of centers between poles.
Final Answer:a force of repulsion