A rectangular wire loop has a R=10Ω resistor on the back as it moves into a region of uniform B=3T field at v=10m/s. The rectangle is w=5cm wide by l=20cm long.
#7A (2 points possible)
As the loop enters the field, which way will the induced current flow?
- unanswered clockwise counterclockwise there will be no induced current
Final Ch
To determine the direction of the induced current, you can use Lenz's Law. Lenz's Law states that the direction of the induced current will be such that it opposes the change in magnetic field.
In this case, as the loop enters the region of the uniform magnetic field, the magnetic field is increasing. So, to oppose this increase in magnetic field, the induced current will flow in such a direction that it creates its own magnetic field that opposes the external field.
Applying the right-hand rule for a conductor, you can determine the direction of the induced current. If you curl your right-hand fingers in the direction of the entering motion of the loop (from left to right), and align your thumb with the magnetic field direction (from bottom to top), then the direction in which your fingers point will give you the direction of the induced current.
Using this method, the induced current will flow counterclockwise in the loop as it enters the field.