A2L Item 239

Goal: Reason with Lenz’s Law

Source: 238-730 Lenz’s Law 2

For which of the following situations will the current flow clockwise?
<table

A) A conducting rectangular loop falls from rest into a magnetic
field directed out of the page.
B) A thin metal strip slides down parallel rails elevated at an
angle q. A constant B field is directed vertically upward.
C) A conducting loop moves in a magnetic field produced by an
infinite current-carrying wire.

1. No situations
2. A
3. A and B
4. A and C
5. A, B, and C

Commentary:

Answer

(4) There is usually a lot of confusion with Lenz’s Law. It is important
to determine what students are using to decide the direction of the
current. Some students despair of ever figuring it out and just guess.
Examining the microscopic motion of charges often helps.