A loop moves toward a stationary magnet. The induced current will:
Correct answer: B. Try to stop the approach
- A. Enhance the motion
- B. Try to stop the approach
- C. Become zero
- D. Become alternating
Explanation
By Lenz's law the induced current sets up a field that opposes the change producing it, so the loop is repelled and work must be done to keep pushing it towards the magnet. That work is the source of the electrical energy generated, which makes Lenz's law a statement of energy conservation. A current that enhanced the motion would create energy from nothing.
This question appeared on the UHS MDCAT 2025 paper, which you can sit online with every answer explained.
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About Lenz's Law
Lenz's law states that the induced current flows in a direction that opposes the change in magnetic flux producing it. Questions connect this rule with Faraday's law, magnetic flux, induced emf and the direction of motion or current, while distinguishing opposition to flux change from opposition to the magnetic field itself.
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