electromotive force

Thân thiện

A student measures the electromotive force of a battery using a voltmeter.

Definition

1. Noun:
   • The rate at which energy is drawn from a source that produces a flow of electricity in a circuit; expressed in volts: It is the electrical potential difference or pressure that drives an electric current through a conducting circuit. It is not a force in the mechanical sense but an energy per unit charge supplied by a source like a battery or generator.

Usage Examples

• Noun:
  • The battery provides an electromotive force of 9 volts to the circuit.
  • Faraday's law of induction describes how a changing magnetic field can generate an electromotive force in a conductor.
  • The unit for measuring electromotive force is the volt.

Advanced Usage

• "Induced electromotive force": An electromotive force generated in a conductor due to a changing magnetic field, as described by electromagnetic induction.

  • The moving magnet created an induced electromotive force in the coil of wire.

• "Back electromotive force (back EMF)": The electromotive force that opposes the change in current which caused it, often generated in electric motors or inductors.

  • The motor's speed can be controlled by managing the back electromotive force.

Variants and Related Words

• EMF (n): A common abbreviation for electromotive force.

  • The EMF of the cell was measured precisely.

• Electromotive (adj): Relating to or producing an electromotive force.

  • The electromotive series lists metals in order of their tendency to lose electrons.

Synonyms

• Voltage: Electrical potential difference, often used interchangeably with electromotive force in many contexts, though technically EMF refers specifically to the source's potential.
• Potential difference: A more general term for the difference in electric potential between two points.

Related Phrases and Concepts

• Electromotive force series: Also called the electrochemical series, a list of metals arranged in order of their standard electrode potentials.

  • Zinc is higher in the electromotive force series than copper.

• Internal resistance: The resistance within a voltage source (like a battery) that causes a drop in the terminal voltage compared to its electromotive force.

  • The battery's electromotive force is 12V, but its terminal voltage is lower due to internal resistance.

Học thuật

Noun

1. the rate at which energy is drawn from a source that produces a flow of electricity in a circuit; expressed in volts

Từ đồng nghĩa

• voltage
• emf