In: Physics
Imagine you have two wire loops lying next to each other on a table. The first one is connected to an AC power supply (like a wall outlet), producing a time-varying current through the wire, which in turn produces a time-varying magnetic field. The second wire loop reacts to this time varying magnetic field according to Faraday's law. Describe the current produced in the second loop.
(I) Increasing current
In the case, when the current in the first loop is increasing, the magnetic flux through the second loop is also increasing. According to Faraday's Law, the induced current will be such that it will try to decrease the magnetic flux. So it will produce the magnetic field opposite to the original magnetic field's direction. Therefore, the two loops will be having currents in different direction. For example, if the current in the first loop is in counterclockwise direction, then the current in the second loop will be in the clockwise direction.
(II) Decreasing current
In the case, when the current in the first loop is decreasing, the magnetic flux through the second loop is also decreasing. According to Faraday's Law, the induced current will be such that it will try to increase the magnetic flux. So it will produce the magnetic field in the same direction of the original magnetic field's direction. Therefore, the two loops will be having currents in the same direction. For example, if the current in the first loop is in counterclockwise direction, then the current in the second loop will also be in the counterclockwise direction.