A Brief Note On The Unit Of Electric Potential

Electric Potential definition is defined as the amount of work that is required to move a unit of electric charge from one referential point to a specific point in an electric field. Ideally, the reference point can be Earth or infinity. However, any point can be used. 

The electrostatic field (E) is a vector quantity and is expressed as a gradient of the electrostatic potential (E), where E is equal to the electric potential energy of any charged particle placed at any location (measured in joules) divided by that particle’s charge (measured in coulombs). The electric field is a property that can be measured by dividing the charge on a particle. To put it simply, an electric potential is energy transferred from charge to charge. 

Electric Potential Work

If a positive charge q is placed between two charged plates, A ( Positively charged) and B (negatively charged). Then, an electric field E is generated. So, The electric force F exerted by the field to move the charge from plate A to B on the charge q will be: 

F = qE 

An equal opposite force ( F= -qE) must be applied. 

Thereby, the amount of work done W in moving a positive charge through a distance d is: 

 W=F×d= -qEd

The Formula Of Electric Potential

The Electric potential definition is known as electric potential energy per unit charge. The formula of Electric potential can be understood with the following: Let us consider a positive charge q to calculate the potential at point A that is distanced at r from a charge q. Then, the force exerted by the test charge q` on the charge q placed at point A will be as such,

F= k(q.q`)/r2 …(1) 

Now, the electric field due to charge q at point A will be given as such, E= F/ q` (since the electric field is force per unit charge) 

putting the value of F from equation 1 we get, 

E= {k(q.q`)/r2}/q` 

or, E= kq/r2 ….(2) 

thus, the value of the electric potential at point A can be given as, 

V= E*r …..(3) 

putting the value of E from equation 2 in equation 3 we get, 

V=( kq/r2)*r 

thus, V= kq/r ….(4) 

hence, equation 4 gives the value of the electric potential at point A V= k q/ r where; 

V= Electric Potential 

k= Coulomb Constant: The coulomb constant or the electric force constant ( k or K) is defined as a proportionality constant in electrostatic equations. 

q= Charge: A charge is defined as the physical property of a matter when placed in an electromagnetic field, causing a force to experience. An electric charge is taken as positive or negative. 

r= distance of separation: if two charges are spherical then the centre to centre distance is of separation. 

The value can be calculated in either static or variable electric fields at a specific time in volts (v) or Joules/ Coulomb. Whenever a voltage is noted, it is referred to as the potential difference between the two points. 

Electric Potential Energy

Electric potential energy is referred to the energy required to move a charge against a given electric field. It is a scalar quantity with only a magnitude but not a direction. It is measured in Joules and denoted by (V) 

The relationship between potential difference and electric potential energy is given by: 

ΔV= ΔU/q

It should be noted that there is a difference in Voltage and Energy. Thereby, Voltage is defined as energy per unit charge. 

Gravitational potential Energy 

It is defined as the stored energy of an object with reference to its vertical position above the Earth’s surface. It is dependent on the mass of the object and the height or the potential to which the object is raised. One can say that the gravitational potential energy is dependent on the object’s mass and height. If an object is twice the mass, it will have twice the potential energy and similarly, if an object is located at twice its height, it will have twice the potential energy. This elaborates the reason for the high positions as high potential energy locations. 

The unit of the Electric Potential

In the honour of Alessandro Volta, who was an Italian chemist, and physicist. He made remarkable contributions to electricity and power. He is known to be the inventor of the electric battery and the discovery of methane is credited to him. The other units of Electric potential are known as; abvolt and Statvolt. Statvolt is defined as a unit of voltage and electric potential used in CGS and gaussian systems. One statvolt is equal to 10-8 volt in relation to the SI units. 

Conclusion

A difference in electrical levels causes the flow of current between two potentials, which are graded as electrical levels. This level is measured in comparison with a reference level. Earth is assumed to be the reference level. Generally, a potential higher than the earth’s potential is considered positive, whereas a potential below is considered negative. Electric potential is measured in volts. When one joule of work is done to transfer a unit charge between two points, one volt is the potential difference between the two points. In other words, 

volt= Joules/ coulomb