The electric potential at a point in an electric field is \( 8\times10^{4}\,\mathrm{V} \). The work done to bring a point charge \( 5\times10^{-9}\,\mathrm{C} \) from infinity to this point in the field is
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → \( 4\times10^{-4}\,\mathrm{J} \)
The electric potential at a point is the work done per unit charge in bringing a charge from infinity to that point, so the work done on a charge \( q \) is \( W = qV \).
\( W = qV = 5\times10^{-9}\,\mathrm{C} \times 8\times10^{4}\,\mathrm{V} \)
\( W = 40\times10^{-5}\,\mathrm{J} = 4\times10^{-4}\,\mathrm{J} \)