emf

Thân thiện

A student measures the emf of a battery using a voltmeter.

Definition

1. Noun:
   • Electromotive force: 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 generated by a source like a battery or generator, which drives current through a circuit.

Usage Examples

• Noun:
  • The battery's emf is 1.5 volts.
  • Measuring the emf of a cell requires a high-impedance voltmeter.
  • The generator produces an emf by rotating a coil within a magnetic field.

Advanced Usage

• "Induced emf": An electromotive force created by a changing magnetic field, as described by Faraday's law of induction.

  • The induced emf in the coil caused a current to flow.

• "Back emf": An electromotive force that opposes the change in current which created it, often seen in electric motors and inductors.

  • The motor's back emf increases with its rotational speed.

Variants and Related Words

• EMF: The common abbreviation for electromotive force.
• Electromotive force: The full term for emf.
• Voltage (n): While often used interchangeably in casual contexts, voltage more precisely refers to the potential difference between two points, which can be caused by an emf or other factors.
• Potential difference (n): The difference in electric potential between two points.

Synonyms

• Electromotive force: The direct synonym.
• Driving potential: A descriptive term for the force that drives current.

Related Phrases and Concepts

• "Source of emf": A device that provides electromotive force.

  • A battery is a common source of emf.

• "Internal resistance": The resistance within a source of emf that causes a drop in the terminal voltage when current flows.

  • The battery's internal resistance reduces the available voltage under load.

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
• electromotive force