A current-carrying wire is surrounded by a magnetic field. The field is either into or out of the screen as shown in the simulation. A current can be induced in the nearby induction loop, and an ammeter detects the current. A graph shows the induced current as a function of time. You can adjust the current through the wire, and so change the magnetic flux through the induction loop. When the induced current is counter-clockwise in the loop the ammeter reading is positive. Similarly, a clockwise induced current corresponds to a negative ammeter reading.

1. Initially the current in the wire is constant at 5 A. Why is the current in the loop zero?
2. Use Lenz’s law to predict the direction of the induced current when you change the current in the wire from 0 to 10 A. Check it out with the simulation.
3. Use Lenz’s law to predict the direction of the induced current when you change the current in the wire from 10 to 0 A. Check it out with the simulation.
4. Use Lenz’s law to predict the direction of the induced current when you change the current in the wire from 0 to -10 A. Check it out with the simulation.
5. Change the current again from 0 to –10A, but this time do it in a way that the magnitude of the induced current is larger than it was the last time. How can you accomplish this?