Physics Lesson 16.8.2 - Magnetic Moment Approach Used to Explain the Lentz Law

Please provide a rating, it takes seconds and helps us to keep this resource free for all to use

★★★★★ [ 1 Votes ]

Welcome to our Physics lesson on Magnetic Moment Approach Used to Explain the Lentz Law, this is the second lesson of our suite of physics lessons covering the topic of Lentz Law, you can find links to the other lessons within this tutorial and access additional physics learning resources below this lesson.

Magnetic Moment Approach Used to Explain the Lentz Law

As we discussed in the previous paragraphs, the key word used to describe the Lentz law is "opposition". Let's recall the situation in which a north magnetic pole moves towards or away from a circular conducting loop.

Opposition to pole movement. When we move the north pole of a bar magnet towards a conducting loop, the magnetic flux through the loop increases and as a result, a current is induced in the loop as discussed earlier. From the tutorial 16.5 "Magnetic Dipole Moment", we know that the loop acts as a magnetic dipole that has its own north and south pole, the moment μ⃗ of which is directed from south to north, as shown in the figure below.The increasing flux when the magnet approaches the loop is opposed by the north pole of the magnetic dipole directed upwards. From the curled right hand rule we can find the direction of the induced current (here anticlockwise) as shown in the figure above.
When the magnet moves away from the coil, the induced current changes direction as the magnetic dipole has its south pole directed upwards.
Opposition to flux change. When the magnet is at rest, there is no flux change. Therefore, no induced current is produced in the loop. This means no induced magnetic field exists inside and around the coil. When the magnet is moved towards the coil (the N-pole of magnet approaching the coil), the flux increases. This brings the induction of an opposite magnetic field B_i (the N-pole upwards) as shown in the figure above. Again, we can determine the direction of the induced current I using the curled right hand rule.
The two above approaches are confirmations of the truthfulness of the Lentz Law discussed earlier.

You have reached the end of Physics lesson 16.8.2 Magnetic Moment Approach Used to Explain the Lentz Law. There are 2 lessons in this physics tutorial covering Lentz Law, you can access all the lessons from this tutorial below.

More Lentz Law Lessons and Learning Resources

Magnetism Learning Material
Tutorial ID	Physics Tutorial Title	Revision Notes	Revision Questions
16.8	Lentz Law
Lesson ID	Physics Lesson Title	Lesson	Video Lesson
16.8.1	Lentz Law
16.8.2	Magnetic Moment Approach Used to Explain the Lentz Law

Whats next?

Enjoy the "Magnetic Moment Approach Used to Explain the Lentz Law" physics lesson? People who liked the "Lentz Law lesson found the following resources useful:

Magnetic Moment Feedback. Helps other - Leave a rating for this magnetic moment (see below)
Magnetism Physics tutorial: Lentz Law. Read the Lentz Law physics tutorial and build your physics knowledge of Magnetism
Magnetism Revision Notes: Lentz Law. Print the notes so you can revise the key points covered in the physics tutorial for Lentz Law
Magnetism Practice Questions: Lentz Law. Test and improve your knowledge of Lentz Law with example questins and answers
Check your calculations for Magnetism questions with our excellent Magnetism calculators which contain full equations and calculations clearly displayed line by line. See the Magnetism Calculators by iCalculator™ below.
Continuing learning magnetism - read our next physics tutorial: Inductance and Self-Induction

Help others Learning Physics just like you