A thin sheet of conductor , when allowed to oscillate in a magnetic field normal to the sheet, then the motion is __

Options

A. damped due to air friction
B. damped due to eddy currents
C. accelerated due to eddy currents
D. not effected by induced currents

Answer

To solve the question regarding the motion of a thin sheet of conductor oscillating in a magnetic field normal to the sheet, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Setup**:
- We have a thin sheet of conductor that is oscillating in a magnetic field. The magnetic field is perpendicular (normal) to the plane of the sheet.

2. **Induced EMF and Eddy Currents**:
- When the conductor oscillates in the magnetic field, the magnetic flux through the sheet changes. According to Faraday's law of electromagnetic induction, a change in magnetic flux induces an electromotive force (EMF) in the conductor.
- This induced EMF leads to the generation of currents within the conductor, known as eddy currents.

3. **Effect of Eddy Currents**:
- Eddy currents flow in loops within the conductor and create their own magnetic fields. These magnetic fields oppose the change in magnetic flux according to Lenz's law.
- As the sheet oscillates, the eddy currents will generate forces that oppose the motion of the sheet. This results in a damping effect.

4. **Conclusion**:
- The motion of the thin sheet of conductor oscillating in the magnetic field is damped due to the eddy currents that are induced in the sheet. Therefore, the correct answer to the question is that the motion is "damped due to eddy current."

### Final Answer:
The motion is damped due to eddy current.

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