Electromagnetism — Lenz’s law comprehension: Does Lenz’s law state that an induced current (or induced emf) always acts to oppose the change in magnetic flux that produced it, thereby opposing the cause of motion or flux change?

Introduction / Context:
Lenz’s law determines the direction (polarity) of induced currents and voltages in electromagnetic induction. It is a qualitative statement that ensures energy conservation and aligns with Faraday’s law. Engineers rely on it when predicting back-emf in motors, inductive kickback in coils, eddy current braking, and transformer polarities.

Given Data / Assumptions:

• Changing magnetic flux through a conducting loop or coil.
• Faraday’s induction principle applies: magnitude of induced emf is proportional to rate of change of linked flux.
• Conventional passive sign convention and standard circuit orientation.

Concept / Approach:
Lenz’s law: the induced emf produces currents whose magnetic field opposes the original change in flux. If flux increases, the induced current creates an opposing field to reduce the increase. If flux decreases, the induced current creates a field that tries to maintain it, resisting the decrease. This opposition manifests as mechanical forces resisting motion (e.g., in generators) or electrical voltages resisting current change (e.g., in inductors).

Step-by-Step Solution:

Verification / Alternative check:
Consider moving a magnet toward a loop: the induced current direction creates a magnetic field repelling the magnet (opposing the approach). Pulling the magnet away flips the current to attract it (opposing separation). This physical opposition is a direct demonstration of Lenz’s law.

Why Other Options Are Wrong:
“Incorrect” conflicts with the definition. Limiting it to DC, to increases only, or to ferromagnetic cores is false—Lenz’s law applies generally to any changing flux linkage in conductive loops.

Common Pitfalls:
Confusing “oppose the change” with “oppose the flux.” It opposes the change in flux, not necessarily the flux itself.

Final Answer:
Correct