alleryStart learning →The electrostatic potential at a point due to a point charge $q$ at distance $r$ is
A$\dfrac{1}{4\pi\varepsilon_0}\dfrac{q}{r}$
B$\dfrac{1}{4\pi\varepsilon_0}\dfrac{q}{r^2}$
C$\dfrac{1}{4\pi\varepsilon_0}\dfrac{q^2}{r}$
D$\dfrac{1}{4\pi\varepsilon_0}\,q\,r$
Answer & Solution
Correct answer: A. $\dfrac{1}{4\pi\varepsilon_0}\dfrac{q}{r}$
1. Potential is work done per unit charge to bring a test charge from infinity to the point.
2. For a point charge this gives $V = \dfrac{1}{4\pi\varepsilon_0}\dfrac{q}{r}$ (varies as $1/r$).
3. The $1/r^2$ expression is the electric **field**, not the potential.
_Source: Samacheer Kalvi Class 12 Physics Vol.1, Unit 1 'Electrostatics', §1.5 / Long Answer Q.7_
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