Question

The SI unit of electric potential is
A. $V{{m}^{-1}}$
B. $C$
C. $N{{C}^{-1}}$
D. $V$

Answer 1

We will see the definition of electrical potential in this question first. The electrical potential is defined by the energy potential of electricity. We will find the SI unit using these expressions after writing the expression for these terms. An electrical potential is the amount of work required to move an electrical charge unit from a reference point to a particular point in an electrical field without generating.

Complete step by step answer:
Imagine a 'q' charge fixed at the origin of a system of coordinates. We're making another ${{q}_{0}}$ charge, which we call the 'test charge'
Moving it from ${{r}_{a}}$ to ${{\text{r}}_{b}}$ under the force influence of $\mathrm{q}.$ The change in the $\Delta U$ potential energy of this two-charge system is given as follows:
$\Delta U=\dfrac{1}{4 \pi \in_{0}} q_{0} q\left(\dfrac{1}{r_{b}}-\dfrac{1}{r_{a}}\right) \ldots \ldots .(1)$
Electric potential difference $(\triangle V)$
It is defined as the electrical potential energy difference per unit test charge.
$\Delta V=\dfrac{\Delta U}{q_{0}}$
$V_{b}-V_{a}=\dfrac{U_{b}-U_{a}}{q_{0}}$
Taking $U_{a}=0$ for infinite initial separation.
The electrical potential at a point is written as:
$V=\dfrac{U}{q_{0}}=\dfrac{1}{4 \pi \epsilon_{0}} q\left(\dfrac{1}{r_{b}}\right)$---(2)
The SI unit of potential that follows from equation 2 is the joule per coulomb. This combination is given the name of
volt(V).
$1 \mathrm{Volt}=1$ joule $/ \mathrm{coulomb}$

So, the correct answer is “Option D”.

Note: The formula for finding electrical potential at a point should be remembered. A potential of zero at a point does not necessarily mean that at that point the electrical force is zero. When the electrical potential at a point is zero, as the test charge moves from infinity to that point, no net work is done by the electrical force.