# Electro Motive Force The purpose of my experiment is to demonstrate the existence of the Electro Motive Force using a Homopolar Motor.

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Electro Motive Force The purpose of my experiment is to demonstrate the existence of the Electro Motive Force using a Homopolar Motor.

 If an electric circuit is made to interact with a magnetic field, then a rotary movement is induced.  If the direction of the current in the circuit is reversed, then the direction of rotation changes.

I assembled the Homopolar Motor using the following items: Magnet Copper wire Battery

First Method I attached the magnet under the battery. I took the copper wire and made it into a coil that could be suspended around the magnet and battery. One end of the coil touched the top end of the battery while the other touched the magnet, thus completing the circuit. Second Method I attached the magnet to a screw which in turn was attached to the bottom end of the battery. I completed the circuit by placing the copper wire between the top end of the battery and the bottom of the suspended magnet.

Faraday's Law is a basic law of electromagnetism that predicts how a magnetic field will interact with an electric circuit to produce an electromotive force (EMF). It is the fundamental operating principle of electrical motors and generators. Fleming’s Left Hand Rule states that when current flows in a wire, and an external magnetic field is applied across that flow, the wire experiences a force perpendicular both to that field and to the direction of the current flow.

Observations after the motor was assembled: First method First method : I saw the copper wire spin around the battery and the magnet when the circuit was completed. Second method Second method : I saw the magnet spin when the circuit was completed. Method Polarity of the Battery Direction of Rotation FIRST METHOD Copper wire rotates clockwise FIRST METHOD Copper wire rotates counter clockwise SECOND METHOD Magnet rotates clockwise SECOND METHOD Magnet rotates counter clockwise

» The rotary movement is due to the presence of the Electro Motive Force. The direction of rotation is based on Fleming’s Left Hand Rule. » Reversing the polarity of the battery changes the direction of rotation. » The speed of rotation is dependent on the charge in the battery! A new battery provides more current, so the rotation is fast. As the battery loses charge, the speed of rotation gradually comes down.

Based on our observations, data and results, we can conclude that: Electro Motive Force “When a Magnetic Field interacts with an Electric circuit an invisible force called the Electro Motive Force is produced”. This is the fundamental operating principle of an Electric Motor.

 ELECTRIC MOTORS  ELECTRIC GENERATORS  LINEAR MOTORS  MAGNETIC LEVITATION

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