How Does a Magnet Affect Compass Direction in a Dual Coil Setup?

[sparkle123]

The north pole of a permanent magnet was held over a coil of wire with a hollow core, as shown. A second coil with a hollow core was connected to the first coil as shown. A magnetic compass needle was placed into the second coil, free to rotate in a vertical circle as shown. If the north pole of the magnet was plunged into the first coil, towards what point will the compass needle rotate?

The answer is C, but I thought it would be D because by Lenz's Law the north pole would be on the left.

 

[mark726]

Hello,

I would like to clarify the answer to this question. The correct answer is indeed C, as the compass needle would rotate towards the south. This is because when the north pole of a magnet is plunged into a coil of wire, it induces a current in the wire that creates a magnetic field with a north pole facing towards the incoming magnet. This north pole then repels the north pole of the compass needle, causing it to rotate towards the south.

The concept of Lenz's Law, which states that an induced current will create a magnetic field that opposes the change in magnetic flux, is still applicable in this scenario. However, in this case, the induced magnetic field is created by the current in the wire, not by the magnet itself.

I hope this clarifies any confusion. Thank you for your interest in this topic.