Define electric potential difference. State the formula for it. Name and define the SI unit of potential difference.

Explanation

Definition of electric potential difference : The electric potential difference (p.d.) between any two points A and B in an electric field is the work done to move a unit positive charge (+ 1 C) from one point A to the another point B against the electric force due to the electric field.
Potential difference (V) between two points
`=("Work done (W)")/("Charge (Q)")`
If potential at point A is `V_A` and that at point B is `V_B`. electric potential difference between points A and B is
`({:("Potential at"),("Final Point B"):})-({:("Potential at"),("Initial Point A"):})=W/Q`
`i.e., V_B - V_A = W/Q`... ....(12.3)
If `V_B - V_A` is denoted by V, `V = W/Q`
Electric potential difference (p.d.) is also known as voltage.
The SI unit of p.d. is volt or joule / coulomb.
Definition of the volt: The potential difference between two points in an electric field is said to be 1 volt if 1J of work is done to move a charge of 1c from one point to another point.
`(1V = (1J)/(1C))`