Electromagnetic Induction and Rate of Flux Change

Steps:

• The ammeter reading indicates induced current from changing magnetic flux through the coil.
• Induced EMF (and current) magnitude depends on the rate of change of magnetic flux, per Faraday's law: EMF = -dΦ/dt.
• Flux change rate increases with faster magnet motion, larger field strength, or more coil turns.
• Evaluate options to find which boosts the flux change rate.

Why C is correct:

• Pushing the magnet faster increases the rate of flux change (dΦ/dt), directly increasing induced EMF and current per Faraday's law.

Why the others are wrong:

• A: Opposite pole reverses flux direction, changing current sign but not magnitude.
• B: Pulling out decreases flux oppositely, likely reversing current without increasing size.
• D: Unwinding turns reduces coil's flux linkage (Φ = NBA), decreasing induced EMF.

Final answer: C