Difference Between EMF and Potential Difference
Introduction
Electromagnetism is a fundamental concept in physics. There are several phrases and units that are quite similar to one another, with just a sliver of difference between them. Two such concepts are "potential difference" and "emf."
What is an Electromotive Force (emf)?
The overall voltage in an electric circuit created by the source or battery is best defined as electromotive force, or emf. The electromagnetic field (EMF) is not a physical force. When the circuit is open, it is the energy necessary to carry a unit positive charge from the negative terminal of the battery to the positive terminal. The underlying voltage produced by a fluctuating magnetic field across a wire or circuit is known as emf. It was also described formally as the force necessary to separate two charges (one positive and one negative) from one another.
Volts are the unit of measurement. The letter 'E' is often used to represent electromotive power (epsilon). If we define emf mathematically, we get: Where 'E' denotes the emf and ECS is the electrostatic field created.
In basic terms, an electromotive force is the greatest voltage that a circuit may achieve.
What is a Potential Difference?
The effort done per unit charge to transport a charge between the negative and positive terminals of a battery is referred to as potential difference. When the battery is used or the circuit is closed, a part of the emf is used to overcome the battery's internal resistance. The potential difference is the amount of energy per unit of charge.
In a circuit of 'I' current, if 'E' is the emf of the battery used in the circuit, 'r' is the internal resistance of the particular battery, and the external resistance of the circuit is 'R,' then E = Ir + IR.
The potential difference between the terminals of the battery, also known as the terminal voltage, is referred to as E – Ir. The emf is symbolised by the sign 'V' and may be measured using a voltmeter (volt).
Magnetic and gravitational fields are frequently referred to as "potential differences." Although their units are different, the principle is the same.
Comparison Table Between EMF and Potential Difference
| EMF |
Potential Difference |
- The energy delivered by the cell to the unit charge is known as E.m.f.
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- The energy wasted as the unit charge flows through the components is known as the potential difference.
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- E.m.f is the source of the problem.
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- The effect is the potential difference.
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- Even when no current is taken via the battery, the emf exists.
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- In the absence of current, the potential difference across the conductor is zero.
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- It is unaffected by circuit resistance.
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- It is directly proportional to the resistance between two measurement places.
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- It does not stay the same.
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- It is always bigger than the gap in potential.
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- It is never greater than emf.
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- Both within and outside the cell, it transfers current.
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- Current is transferred between two places in the cell using the potential difference.
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