A2L Item 244

Goal: Hone skill at using Lenz’s Law

Source: 283-CTQsas36

Consider the four situations below in which a wire loop lies in the
plane of a long wire. In which case(s) is the induced current in the
loop in the counterclockwise direction? [Note: if no velocity is
indicated, the loop is stationary.]

  1. A only
  2. B only
  3. C only
  4. D only
  5. A and B
  6. C and D
  7. All cases.
  8. None of the above.



  1. Discussing each of the cases is valuable. Students have difficulty
    recognizing that the induced current is in a direction that causes the
    field of the induced current to compensate for the change in flux. Even
    when they nominally understand that, they have trouble reliably applying
    the right hand rule.