Magnetic pole interaction: When the north poles of two bar magnets are brought close together, what happens?

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:

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