How do Lenz's Law and the right hand rule work together in electromagnetism?

[brianll]

I am having trouble understanding how the right hand rule works with lenz's law. Please explain

 

[Delphi51]

Welcome to PF, brian. Lenz's law is an interesting and useful shortcut for working out the direction of a force. The hand rule is the basic and longer way to work out many of these situations. There isn't much more to be said unless you are interested in a specific situation.

The classic demo for Lenz' law is dropping a strong magnet through a copper pipe. It falls s l o w l y. Lenz' law says the magnetism induces a current in the pipe which acts to oppose the motion of the magnet.

A similar apparatus has a piece of copper pipe suspended by threads so it is free to move. When you pull the magnet out, Lenz' law says the copper pipe tries to hold on to the magnet and you can see this because the magnet pulls back on the pipe and makes it move. Here is the explanation of that effect using the hand rule:

 

[brianll]

Hi Delphi. How do you figure out if the magnetic flux is increasing or decreasing?

 

[Delphi51]

In the example, the magnetic flux is from a permanent magnet and is constant.

 

[rwisz]

Lenz's Law and the right hand rule are both important concepts in the study of electromagnetism. Lenz's Law states that when a changing magnetic field passes through a conductor, it induces an electromotive force (EMF) that creates a current in the conductor. This current then creates its own magnetic field that opposes the original changing magnetic field.

The right hand rule is a method used to determine the direction of the induced current in a conductor. It states that if you point your thumb in the direction of the original magnetic field, and your fingers in the direction of the conductor's motion, then the direction of the induced current will be perpendicular to both your thumb and fingers.

To understand how the right hand rule works with Lenz's Law, let's consider an example. Imagine a bar magnet moving towards a coil of wire. As the magnet moves, it creates a changing magnetic field that passes through the coil. According to Lenz's Law, this changing magnetic field will induce an EMF in the coil, creating a current. The right hand rule can be used to determine the direction of this current.

If we point our thumb in the direction of the magnetic field (from the north pole to the south pole of the magnet), and our fingers in the direction of the coil's motion (towards the magnet), then our palm will face in the direction of the induced current. This means that the current will flow in a direction that creates a magnetic field that opposes the original changing magnetic field of the magnet. This is known as the "back EMF" and it follows Lenz's Law.

In summary, Lenz's Law explains the relationship between a changing magnetic field and the induced current in a conductor, while the right hand rule helps to determine the direction of this induced current. Together, these concepts are fundamental to understanding the behavior of electromagnetism and its applications in various fields of science and technology. I hope this explanation helps you better understand the connection between Lenz's Law and the right hand rule.