Two point charges and are placed apart on a straight line

PHYSICS · Single correct · A Level · Physics · Fields and their consequences · Fields and their consequences

Problem

Two point charges +q+q and −q-q are placed 10 cm10\,\text{cm} apart on a straight line. Point PP lies exactly midway between them on the line joining the charges. What is the electric potential at PP? (a) +14πε0 2q0.05 m+\dfrac{1}{4\pi\varepsilon_0}\,\dfrac{2q}{0.05\,\text{m}} (b) +14πε0 2q0.10 m+\dfrac{1}{4\pi\varepsilon_0}\,\dfrac{2q}{0.10\,\text{m}} (c) Zero, because the potentials due to the two charges cancel each other (d) Infinite, because the electric field at PP is zero

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