Question

The SI unit of potential difference is:
(a). Ohm
(b). Ampere
(c). Ohm-meter
(d). Volt

Answer 1

- Hint: Instead of thinking about electrostatics, think about an electric circuit. A battery has a potential difference. Potential difference can be treated as voltage. Their units are also the same.

Complete step-by-step solution -
The electric potential difference in simple words can be stated as the amount of work done in bringing a positive test charge from one point to another against some electric field.
Mathematically,
$\text{Potential difference }(V)={\displaystyle \frac{\text{Workdone }}{\text{Charge }}}$
Here work done (W) is equal to,
$$W=Fx$$, where x is the distance between the two terminals.
$$W=qEx$$, i.e. here the force is $$qE$$. This force is being acted against the pre-existed electric field.
The SI unit of potential or potential difference is Volt. One Volt may be defined as the one joule of work-done to move a charge of one coulomb.
So, its Dimension formula is $$\left[\text{M}{\text{L}}^{\text{2}}{\text{T}}^{\text{-3}}{\text{A}}^{\text{-1}}\right]$$
The correct option is d.

Additional Information:
Energy is not the same as voltage. Voltage can be defined as the energy per unit charge. That’s why car batteries can store more energy than the motorcycle battery even if they have the same voltage or potential difference. Generally, they are 12 V batteries.
Ohm is the SI unit of electrical resistance.
Ampere is the SI unit of current
Ohm-meter is the SI unit of electrical resistivity

Note: There is a physical difference between the term potential and potential energy. Do not confuse that. Potential energy can be stored in some way to do some work. Potential energy has units of energy, i.e., the joule. Potential energy can find out from the potential difference by multiplying it with charge.