What is the difference between potential difference and electromotive force?
EMF, electromotive force, refers to the voltage developed by an electrical source. Potential difference refers to the observed difference in voltage between any two points in an open circuit. They are not quite the same thing.
The Leclanché battery wet cell was the forerunner of the modern zinc-carbon battery (a dry cell). The addition of zinc chloride to the electrolyte paste raised the e.m.f. to 1.5 volts.
- A mercury battery (also called mercuric oxide battery, or mercury cell) is a non-rechargeable electrochemical battery, a primary cell. Mercury batteries use a reaction between mercuric oxide and zinc electrodes in an alkaline electrolyte.
- Electromotive Force and Internal Resistance. The electromotive force (e) or e.m.f. is the energy provided by a cell or battery per coulomb of charge passing through it, it is measured in volts (V). It is equal to the potential difference across the terminals of the cell when no current is flowing.
- legal Definition of local action. : an action (as for trespassing) that must be brought in the venue that has jurisdiction over the situs or is otherwise designated by law — compare transitory action.
The terminal voltage of a cell is the potential difference between its electrodes. A voltmeter cannot be used to measure the emf of a cell because a voltmeter draws some current from the cell. To measure a cell's emf a potentiometer is used since in a potentiometer measurement no current is flowing.
- Electromotive Force (EMF) The electromotive force (EMF) is the maximum potential difference between two electrodes of a galvanic or voltaic cell. This quantity is related to the tendency for an element, a compound or an ion to acquire (i.e. gain) or release (loss) electrons.
- To be completely accurate, if the magnetic flux through a coil is changed, a voltage will be produced. This voltage is known as the induced emf. The magnetic flux is a measure of the number of magnetic field lines passing through an area. If the flux changes, an emf will be induced.
- The terminal voltage of a cell is the potential difference between its electrodes. A voltmeter cannot be used to measure the emf of a cell because a voltmeter draws some current from the cell. To measure a cell's emf a potentiometer is used since in a potentiometer measurement no current is flowing.
The strength of an electromotive force is measured in the unit "Volts", named after Alessandro Volta, an Italian physicist credited with inventing the electric battery. (Not named after Voltaire.) We almost always refer to electromotive force as voltage, but EMF and Voltage are just two names for the same thing.
- EMF meters detect fields emitted by moving electrically charged objects. Electromagnetic field theory lies at the combination of an electric field, produced by a charged object, and the magnetic field created when the charged object moves.
- Similar to the way that electromotive force (EMF) drives a current of electrical charge in electrical circuits, magnetomotive force (MMF) 'drives' magnetic flux through magnetic circuits. The term 'magnetomotive force', though, is a misnomer since it is not a force nor is anything moving.
- The foundation of effective EMF protection is measurement, avoidance and protection. It means minimizing your exposure to EMFs while simultaneously supporting your body with the raw materials it needs to protect and repair itself.
Updated: 16th October 2019