Important Topic of Physics: Potential Difference

# Important Topic of Physics: Potential Difference

## Introduction

The amount of potential energy per unit of charge at a given location is expressed as electric potential, which is a location-dependent variable. When a Coulomb of charge (or any given amount of charge) has a big amount of potential energy in a given location, such a site is called a high electric potential position. Similarly, if a Coulomb of charge (or any given amount of charge) has a minimal amount of potential energy at a specific position, that region is referred to as a low electric potential site. We’ll start referring to the difference in electric potential between two points as we apply our notions of potential energy and electric potential to circuits. As we’ll see, electric circuits are all about the flow of charge between different sites and the energy loss and gain that goes along with it. The notion of electric potential was applied to a basic battery-powered electric circuit. It was taught that in order to move a positive test charge from the negative terminal to the positive terminal, work must be done on it. This work would enhance the charge’s potential energy and consequently its electric potential. The electric potential energy of the positive test charge diminishes as it goes through the external circuit from the positive to the negative terminal, and by the time it returns to the negative terminal, it is at a low potential. If the circuit is powered by a 12-volt battery, each coulomb of charge gains 12 joules of potential energy as it passes through the battery.

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## Overview

The difference in electrical potential between two places is known as potential difference. When two positive charges come close together, they repel each other.

When two negative charges come near together, they repel each other. A positive and negative charge, on the other hand, attract each other when brought close together. When these two diametrically opposed charges are joined, they can be put to use. To light a bulb or operate any electrical tool, equipment, mobile phone, or home appliance, we require a positive (+) and a negative (–). An electric potential is the ability of charged particles to perform work. As a result, two opposite charges have a potential difference or Potential Difference. The volt is the unit of potential difference (pd).

Alessandro Volta is the name of the unit of Potential Difference (Volt). A volt is a unit of measurement for electric potential. Electrical potential is a sort of potential energy that describes the amount of energy that may be produced if an electric current were to flow. When an electric current of one ampere dissipates one watt of power between two points of a conducting wire, one volt is defined as the difference in electric potential between those places. It’s also the potential difference between two parallel, infinite planes spaced 1 metre apart that produces a 1 newton per coulomb electric field.

## Terminal potential difference of a cell

When the circuit is turned on, the terminal voltage is the potential difference across the terminals. EMF, on the other hand, is the highest potential difference that a cell or generator may produce when no current flows through it. When the terminal voltage is measured using a voltmeter, the electromotive force is measured using a potentiometer. Because of the potential drop caused by the current passing through the internal resistance of the cell, the terminal voltage is always lower than the EMF. Terminal voltage does not retain constancy, but EMF is a cell’s characteristic constant. A cell’s terminal potential difference is defined as the potential difference between its two electrodes in a closed circuit. When current is drawn from a cell, the terminal potential difference is less than the emf of the cell (i.e., during discharging of the cell). When a current flows, the internal resistance r of a voltage source influences the output voltage. The terminal voltage V of a device is given by V = emf Ir, where I is the electric current and is positive when flowing away from the positive terminal of the voltage source.

## Define Potential difference

The difference in electrical potential between two points is simply defined as potential difference. When two positive charges are brought close together, they repel each other.

The amount of work energy required to move an electric charge from one point to another is referred to as the potential difference. The volt is the unit of potential difference.

The work or energy released in the transmission of a unit quantity of electricity from one point to another is represented by the difference in potential between two points.

## Relation between internal resistance emf and terminal potential difference of a cell

All voltage sources have two basic components: an internal resistance r and an electrical energy source with an electromotive force characteristic (emf). So, the emf is the potential difference between a source when no current is flowing through it and when current is flowing through it. The internal resistance r of the voltage source, on the other hand, influences the output voltage when the current passes through it. Because of the voltage drop across the internal resistance of the device, the terminal voltage of a battery is smaller than the electromotive force(emf) when it is discharging. If current flows “backwards” from positive to negative poles in a battery, the terminal voltage can be estimated using the battery’s emf and the voltage drop across the internal resistance.

Let E be the emf and V be the terminal voltage. With a load R, the current flowing I, and internal resistance r, the equation can be written as –

E ⁄R+r

The potential difference between the terminal voltages is computed as follows:

V=I.R=ER ⁄R+r

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## FAQs

##### What is the difference between voltage and potential difference?

The amount of labour required to transfer a unit charge from one place in an electric field to another is defined as the electrical potential difference. In other terms, the potential difference is the difference between the two charged bodies' electric potentials. The electrical potential V of a position in the electrical field is such that the electric potential energy required to place a particle of charge q at that position is the product of the particle's charge q and the position's potential V(t).

##### What does it indicate when two points have a potential difference of 1 V?

The potential difference between the two points is 1V if 1J of work is necessary to transport a charge of amount 1C from one point to another.

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