Electromagnetism 3b - Faraday's Law and Lenz' s Law

A description of Lenz's Law and how it relates to Faraday's Law of induction. Includes a couple of examples of how to determine the polarity of an induced magnetic field as well as determine the direction of induced current and polarity induced voltage on an electromagnet in a changing magnetic field.

Copper Tube Animation Website: http://www.magnet.fsu.edu/education/tutorials/slideshows/eddycurrents/index.html

Category:

Education

Tags:

• electromagnets
• Faraday's Law
• Lenz's Law
• Electromagnetic Induction
• Induced voltage

[tarbidian]

If the motion of the electromagnet is toward the permanent magnet, the induced pole on the electromagnet will be the same polarity as that on the permanent magnet to try to prevent you from moving the electromagnet closer. Then use the right hand rule to figure out which way current is going (conventional current)

[Luckier8]

@jozet77 nonono you have it backwards, the video is correct. The magnetic field lines come out of the north pole of the induced magnet, this opposes the north pole of the permanent magnet on the left. Right hand rule says that the current is moving up on the left side of the coil so that the magnetic field it creates will go toward the left, acting like the north pole of a magnet. Like poles oppose, therefore opposing the motion and conserving energy! Gotta love physics!!

[Luckier8]

@jozet77 nonono you have it backwards, the video is correct. The magnetic field lines come out of the north pole of the induced magnet, this opposes the north pole of the permanent magnet on the left. Right hand rule says that the current is moving up on the left side of the coil so that the magnetic field it creates will go toward the left, acting like the north pole of a magnet. Like poles oppose, therefore opposing the motion and conserving energy!

[jozet77]

the current should be going down, cause that would create an opposite magnetic field towards the movement....??