Magnetic repulsion requires like poles facing each other

Steps:

• Identify materials: Iron is ferromagnetic and can be magnetized by induction; copper is non-magnetic.
• Analyze A: Magnet's S-N poles near iron bar induce opposite poles, causing attraction.
• Analyze B: Magnet's S-N near copper bar; no induction, so no repulsion or attraction beyond weak effects.
• Analyze D: Two magnets with like poles (N-N or S-S) facing, leading to direct repulsion.

Why D is correct:

• Like magnetic poles repel each other per the basic law of magnetism.

Why the others are wrong:

• A: Induced magnetism in iron creates opposite poles, resulting in attraction.
• B: Copper lacks magnetic properties, so no repulsion occurs.
• C: Arrangement shows unlike poles or non-ferromagnetic setup, causing attraction or no force.

Final answer: D