Lecture 31  iq27

Demo: Levitation of a cubic magnet

Jumping ring

Falling magnet within a metal tube

A simple Faraday’s law demo

Comments from Faraday’s learning module.

1. Demo with a magnet, a solenoid and a galvanometer

o Galvanometer readings due to increasing/decreasing of the magnetic flux.

o Increasing magnetic flux (out of the paper) leads to a CW curly induced E-pattern.

2. Lenz law: Current loop has magnetic inertia. Change of magnetic flux is canceled by the Bind (induced magnetic field) contribution.

3. Falling magnet (clicker 30-3)

4. Jumping ring

5. Levitation of a magnet IQ 31.3.1

6. Clicker 30.1 Evaluate <-d phi /dt>

7. One more exercise: IQ31.4.1

Concluding line in LM comments

Announcement:

Re: Adjustment on present lesson plan

Our lectures are slightly behind our original lesson plan. The updated lesson plan is as follows.

o Postpone the due date of ch23.h2 from the coming Sunday to next Tuesday.

o Due dates of ch23.h3 and ch24.h1 will be on the Wednesday of the following week. (Using present lesson plan notation, it is “W”)

o Ch24.h2, ch24.h3 on Su.

o Ch24 h4, ch24.h5 on W

o Ch25-h1 on Su

Midterm3 will now cover the exam materials only through ch23-h2.Notice that the inductance and the LR circuit are covered in ch23-h2. They will be included in the exam. On the other hand problems which involve LC circuits only appear in ch23-h3. They will not be included in this exam.