Relative motion determines induced EMF

Steps:

• Faraday's law states induced EMF equals negative rate of change of magnetic flux through the coil.
• Magnetic flux depends on the relative position of the magnet and coil.
• Relative velocity between magnet and coil determines if flux changes over time.
• Zero relative velocity means constant flux, so zero induced EMF and zero ammeter reading.

Why B is correct:

• Coil and magnet moving at same speed in same direction gives zero relative velocity, so flux remains constant and induces zero EMF (Faraday's law).

Why the others are wrong:

• A: Opposite directions double relative speed, causing rapid flux change and induced current.
• C: Coil moving away from stationary magnet increases distance, decreasing flux and inducing current.
• D: Magnet moving toward stationary coil decreases distance, increasing flux and inducing current.

Final answer: B