Chapter 21, Problem 68A

To determine

To find: The SI unit used for measuring electric potential energy. Also, the SI unit of electric potential difference.

Answer to Problem 68A

The SI unit of electric potential energy is $\text{Joules(J)}$.

The SI unit of electric potential difference is $\text{Joules/Coulomb(J/C)}$.

Explanation of Solution

Introduction:

The electric potential energy in electrostatics is defined in such a way that its change from one value to another is the work done in moving a charge from one point to another in an electric field.

The electric potential difference is the work done on a unit test charge for moving it from one point to another in an electric field.

The SI unit used to measure electric potential energy is Joules denoted by J. It can be mathematically expressed as,

$\Delta PE=W_q$

It is dependent on the quantity of charge involved.

Electric potential difference can be mathematically expressed as,

$\Delta V=\frac{W_q}{q}$

Since the work done has a SI unit of Joules and the charge has an SI unit of Coulombs, the SI unit of electric potential difference is Joules/Coulomb or J/C

Conclusion:

The SI units for electric potential energy is Joules and for electric potential difference is Joules/Coulomb.