- Electric Potential Definition: Electric potential is defined as the work needed to bring a unit positive charge from infinity to a point in an electric field.
- Potential Difference: The potential difference between two points is the work needed to move a unit positive charge from one point to another.
- Units of Electric Potential: The unit of electric potential is the volt, defined as one joule of work per one coulomb of charge.
- Electric Potential of Charged Bodies: A charged body can do work by attracting or repelling other charges, which is its electric potential.
- Electric Potential Calculation: Electric potential at a point due to a charge can be calculated using the work done to move a unit positive charge.
Similarly, the potential difference between two points is defined as the work required to bring a unit positive charge from one point to the other.
When a body is charged, it can attract an oppositely charged body or repel a similarly charged body. This ability to do work is defined as the electrical potential of the body.
If two electrically charged bodies are connected by a conductor, electrons flow from the lower-potential body to the higher-potential body, creating a current. This flow depends on the potential difference between the bodies and the resistance of the conductor.
Electric potential of a body is its charged condition, which determines whether it will receive or give up electric charge to another body.
Electric potential is graded as an electrical level, and the difference between two levels causes current to flow. This level is measured from a reference zero level, with the earth’s potential taken as zero. Electric potential above this level is positive, and below it is negative.
The unit of electric potential is the volt. To bring a unit charge from one point to another, if one joule of work is done, then the potential difference between the points is said to be one volt. So, we can say,
If one point has an electric potential of 5 volts, then we can say that 5 joules of work must be done to bring one coulomb of charge from infinity to that point.
If one point has a potential of 5 volts and another has a potential of 8 volts, then 8 – 5, or 3, joules of work must be done to move one coulomb from the first point to the second.
Potential at a Point due to Point Charge
Let us take a positive charge + Q in space. Let us imagine a point at a distance x from the said charge + Q. Now we place a unit positive charge at that point. As per Coulomb’s law, the unit positive charge will experience a force,
Now, let us move this unit positive charge by a small distance dx towards the charge Q.
During this movement, the work done against the field is,
So, the total work to be done for bringing the positive unit charge from infinity to distance x is given by,
As per definition, this is the electric potential of the point due to charge + Q. So, we can write,
Potential Difference between Two Points
Let us consider two points at distances d1 meters and d2 meters from a charge +Q.
We can express the electric potential at the point d1 meters away from +Q as,
We can express the electric potential at the point d2 meters away from +Q as,
Thus, the potential difference between these two points is
