Lenz's law states that the direction of induced emf or current is such as to oppose the cause that produces it. This cause is the change in magnetic flux, and the law is a direct consequence of conservation of energy.

• If a north pole approaches the loop and the linked flux increases, the front face of the loop must behave as north pole to oppose the approach.
• That induced face polarity then fixes whether the current is clockwise or anticlockwise for the given observer.
• Trap: opposing the magnet's existence instead of opposing the increase or decrease in flux that the motion produces.

The relative-motion table combines three linked outputs: current direction, loop-face polarity, and attractive or repulsive force. Each row follows from the single rule that the induced current opposes the cause of induction.

• Increasing cross-type flux and decreasing cross-type flux do not give the same current direction because the required opposition changes.
• Attractive or repulsive force is not chosen directly; it follows from the induced loop-face polarity needed to oppose the motion or flux change.
• Trap: memorising one row mechanically and then applying it to all four relative-motion situations without checking whether flux is increasing or decreasing.