Profile
Settings
Refer your friends
Sign out
Introduction
The potential difference between the two points reflects the work or energy released in the movement of a unit quantity of electricity from one point to the other. This is a key topic for the Class XI examinations, among others. Subjects in the Class XI curriculum are linked to a variety of courses, and their ramifications are discussed.
Potential Difference
The potential difference is measured by the amount of effort required to move a unit charge from one location in an electric field to another. In other terms, the potential difference is the difference in the electric potentials of two charged substances.
When one charged body has a different electric potential than another charged body, the two bodies are said to have a potential difference. Both bodies are under stress and pressure as they strive to reach their full potential.
Unit: Volt is the unit of potential difference.
Terminal Potential Difference
A terminal potential difference is a potential difference across a cell in a circuit. Ohm’s law states that the current flowing through a conductor is directly proportional to the voltage put across it. We may simply pick the proper choice by applying Ohm’s law correctly.
We know that E is present in the cell. The electromotive force (emf) of the cell is denoted by E. The energy supplied by the cell into the circuit is referred to as electromotive force. Internal resistance is symbolized by the letter r. E is the energy of the cell, however, because of the existence of an internal resistor, part of this energy is pulled out of the circuit by the internal resistor. As a result, the voltage drops somewhat. The voltage reduction is proportional to the reciprocal of the current in the circuit and the internal resistance of the cell. The potential difference is calculated by subtracting this decrease from the cell’s energy.
V=E−Ir
This result gives a relation between EMF and potential difference or terminal voltage.
The terminal voltage of a cell equals the emf of the cell only if the internal resistance is zero and the circuit is open. A closed circuit is triggered by a switch and requires the switch to complete the circuit loop, allowing current to flow, whereas an open circuit is one in which the switch is open and current will not flow since the continuity is broken. Do not mix up an open with a closed network.
The electromotive force is the work done by the cell inflowing the unit charge through the full circuit.
It is symbolized by the letter E. Therefore, E = W/q…………….(1)
Where W denotes the work done by the cell in moving charge, q around the circuit.
∴
E = J/ C
volt is the unit of measurement of E.
If q = 1C and W = 1J, then E = 1 J/ C = 1 volt
The value of e.m.f. for one cell is constant and varies between cells. For example, the e.m.f. of a voltaic cell is 1.08 volt, that of a Daniell cell is 1.12 volt, and that of a dry cell is 1.5 volt.
Important Considerations
- Although we refer to e.m.f. As force, it is energy provided by the cell to unit charge for flow through the circuit.
- If external resistance is placed between the cell’s terminals, the potential difference between the terminals is the cell’s ‘Terminal voltage.’
- When no external resistance is connected between the terminals, the potential difference equals the cell’s e.m.f.
The terminal potential difference or terminal voltage of the cell is the work done by the cell in passing a unit positive charge from one terminal to the other terminal over external resistance in a circuit. As a result, terminal voltage V = Wext/ q………..(2), where Wext denotes the work done by the cell in passing q charge across the external circuit.
If R is the external resistance in the circuit and I is the current flowing, then V = Wext/ q = iR (according to Ohm’s law).
Similarly, if r represents the cell’s internal resistance, then the potential drop, i.e., the energy wasted owing to internal resistance r, v = ir.
Conclusion
When a Coulomb of charge (or any given amount of charge) has a comparatively significant amount of potential energy in a specific position, that area is considered to have a high electric potential location. Similarly, if a Coulomb of charge (or any given amount of charge) has a very tiny amount of potential energy at a specific position, that area is considered to have a low electric potential location. When we start applying our notions of potential energy and electric potential to circuits, we’ll start talking about the difference in electric potential between the two places.
