Two charges, + 20 \( \mu \)C and + 40 \( \mu \)C are placed at a separation of 4 cm. The electric potential due to the pair at the middle point of the line joining the two charges is
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 27 MV
Potential is a scalar, so the potential at a point due to several charges is the algebraic sum of the potentials due to each.
\( r = 2\,\mathrm{cm} = 0.02\,\mathrm{m} \)
\( q_{1} = 20\times10^{-6}\,\mathrm{C} \)
\( q_{2} = 40\times10^{-6}\,\mathrm{C} \)
\( \displaystyle V = \frac{k(q_{1}+q_{2})}{r} = \frac{9\times10^{9}\times60\times10^{-6}}{0.02} = 2.7\times10^{7}\,\mathrm{V} = 27\,\mathrm{MV} \)