Question

Foucault currents are also called

Answer 1

Step1: Eddy's current

1. Eddy currents are the currents that are induced in a conductor whenever the amount of linked magnetic flux with the conductor changes.
2. These were discovered by Foucault in the year 1895 and hence they are also called Foucault currents.
3. This effect is employed in eddy current brakes which are used to stop rotating power tools quickly when they are turned off.
4. The Foucault current is another name for an eddy current.
5. Eddy currents are electric current swirls that are induced within conductors by a changing magnetic field (self-inductance).
6. The principle of Eddy current is based on Faraday's law of induction.

Step2: Eddy's current flow

1. Eddy current always acts in a plane perpendicular to the magnetic field and flows in a closed loop within the conductors.
2. The size of the current in a given circle is proportional to the strength of the magnetic field, the circle's area, the rate of magnetic flux, and, inversely, the material's resistivity.
3. These circling flows inside a piece of metal look enigmatically like Eddies or whirlpools in a fluid when charted/graphed.
4. Demonstrating with the help of a diagram.

Step 3: Uses of eddy's current

1. Eddy currents are utilized in automobile speedometers to determine a vehicle's speed. A speedometer is made up of a spinning magnet that rotates according to the vehicle's speed, causing Eddy Current in the drum. The pointer attached to the drum indicates the vehicle's speed when it rotates in the direction of the rotating magnet.
2. Magnetic brakes: When you apply the brakes, the metal wheels are exposed to a magnetic field, which causes the wheels to generate eddy currents. The wheels slow down due to the interaction between the eddy currents and the applied magnetic field.
3. In induction furnaces: Eddy current is employed in induction furnaces to provide a uniform temperature increase. Due to the enormous emf created, massive eddy currents begin to flow in quickly changing magnetic fields. This results in extremely high temperatures. A coil is twisted around a constituent metal and placed in a high-frequency magnetic field that oscillates rapidly.
4. Free-fall devices (for detecting coins in vending machines): Eddy current is used in vending machines to detect counterfeit coins and notes. As the coins pass through a stationary magnet, eddy currents slow them down.

Hence, Foucault's current is also called Eddy current or Induced current.