State Lenz's Law.

• A. The Induced EMF in Any Circuit Is Always in a Direction to Oppose the Effect That Produced It.
• B. The Induced EMF Is Always in the Same Direction as the Cause.
• C. The Induced EMF Is Always Zero.
• D. The Induced EMF Direction Depends on the Material of the Coil.

Answer: (A)

Lenz's Law tells us that the induced EMF and the resulting current always act to oppose the change in magnetic flux that produced them. This opposition is built into Faraday’s law as EMF = -dΦB/dt, where the negative sign signals that the induced effect resists the change.

Think of a magnet moving toward a coil: the magnetic flux through the coil is increasing, so the induced current creates its own magnetic field that repels the magnet, opposing the approach. If the magnet moves away, the flux decreases, and the induced current produces a field that tries to keep the flux from dropping, effectively pulling the magnet back. This opposing action is the core idea.

The alternative that the EMF always points in the same direction as the cause is incorrect because the direction is determined by opposing the flux change, not by mirroring the original cause. The EMF is not always zero, since a changing flux is what drives it. And the direction does not depend on the coil’s material; it depends on how the magnetic flux through the circuit is changing.