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A rectangular conducting loop of wire is approximately half-way into a magnetic field B (out of the page) and is free to move. Suppose the magnetic field B begins to decrease rapidly in strength

Requried:
What happens to the loop?

1. The loop is pushed to the left, toward the magnetic field.
2. The loop doesn’t move.
3. The loop is pushed downward, towards the bottom of the page.
4. The loop will rotate.
5. The loop is pushed upward, towards the top of the page.
6. The loop is pushed to the right, away from the magnetic field

User Brianfit
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1 Answer

4 votes

Final answer:

With the decrease in magnetic field strength, an induced current will create a magnetic field that opposes the change, exerting a Lorentz force that pushes the conducting loop to the left, towards the magnetic field, according to Lenz's Law and the right-hand rule.

Step-by-step explanation:

The question relates to the concept of electromagnetic induction in physics. When the magnetic field B begins to decrease rapidly in strength, a rectangular conducting loop that is half-way into the magnetic field will experience a change in magnetic flux through it. According to Faraday's Law and Lenz's Law, an electromotive force (emf) will be induced in the loop, which causes a current to flow in such a way as to oppose the change in flux. The current induced within the conducting loop will create its own magnetic field that opposes the decrease in the external magnetic field.

Applying Lenz's Law, since the external magnetic field is directed out of the page and is decreasing, the induced current will circulate in a direction that creates a magnetic field into the page, attempting to maintain the original magnetic flux. Therefore, the loop will experience a force called the Lorentz force, which acts perpendicular to the direction of the current and the magnetic field. Based on the right-hand rule (RHR-1), the left side of the loop will experience a force pushing it to the left, toward the existing magnetic field. Thus, the correct answer to what happens to the loop is:

  • The loop is pushed to the left, toward the magnetic field.

User Antje Janosch
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