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Guilherme Mazui

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What is the Difference Between EMF and Voltage?

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The main difference between EMF (Electromotive Force) and voltage lies in their definitions and application within electric circuits:

  1. EMF:
  • It is the voltage generated within an electric source, such as a battery or a generator.
  • It is the maximum potential difference between two points of a battery when no current flows from it.
  • The SI unit of EMF is volts, and its formula is E = V + Ir, where E is the electromotive force, V is the voltage, I is the current, and r is the internal resistance.
  1. Voltage:
  • It is the potential difference between two points in a magnetic field or an electric field.
  • It is the difference between the electrical states on the poles of a battery or a source.
  • The SI unit of voltage is also volts, and its formula is V = IR, where V is the voltage, I is the current, and R is the resistance.

Some other key differences between EMF and voltage include:

  • EMF is caused by electrically charged particles as a result of the separation of electrons from atoms, while voltage is caused only in the electric field.
  • EMF is always constant, while voltage can vary due to energy loss or resistance in the circuit.
  • An EMF meter is used to measure EMF, while a voltmeter is used to measure voltage.

In summary, EMF is the voltage generated within an electric source, while voltage is the potential difference between two points in a magnetic or electric field. Both EMF and voltage are measured in volts, but they represent different concepts within electric circuits.

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  • What is the Difference Between EMF and Voltage?
  • Comparative Table: EMF vs Voltage

    • Comparative Table: EMF vs Voltage

    Here is a table comparing the differences between EMF (Electromotive Force) and Voltage:

    Basis of Difference EMF Voltage
    Definition EMF or electromotive force is the measure of energy given by a source of power (e.g., a battery) to each Coulomb of charge. The difference in the electric potential between two points of an electric circuit is known as voltage. It is also called potential difference, electric pressure, or electric tension.
    Unit Both EMF and voltage are measured in volts. Voltage can be used to represent the difference in potential of any two points of an electric circuit.
    Source EMF is generated by one or more cells or a changing magnetic field in a solar cell. Voltage is mainly developed between the two poles of the electric circuit, such as between the anode and cathode of a battery.
    Dependence The magnitude of the EMF depends on the change in the magnetic field. The voltage depends on the magnitude and resistance of the current.
    Symbol EMF is denoted by the symbol ε (or E). Voltage is denoted by the symbol V.

    In summary, both EMF and voltage are measured in volts, but they represent different electrical quantities. EMF is the energy given to each Coulomb of charge by a power source, while voltage is the difference in electric potential between two points in an electric circuit.

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    Guilherme Mazui

    Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.