Two point charges, \( q_{1} = 3\,\mu\mathrm{C} \) and \( q_{2} = -2\,\mu\mathrm{C} \), are placed 6 cm apart. The magnitude of the electric force between them is
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → \( 15\,\mathrm{N} \)
Coulomb's law gives the magnitude of the force between two point charges, \( F = k\,|q_{1}q_{2}|/r^{2} \).
\( q_{1} = 3\times10^{-6}\,\mathrm{C} \)
\( |q_{2}| = 2\times10^{-6}\,\mathrm{C} \)
\( r = 6\,\mathrm{cm} = 0.06\,\mathrm{m} \)
\( \displaystyle F = \frac{9\times10^{9} \times 3\times10^{-6} \times 2\times10^{-6}}{(0.06)^{2}} = \frac{5.4\times10^{-2}}{3.6\times10^{-3}} = 15\,\mathrm{N} \)
The force is attractive, because the charges are unlike; only its magnitude is asked.
Note: NTA picked this question from an NCERT (2026-27) exercise and changed the figures. Do not ignore NCERT while practising numericals.
NCERT (2026-27):
Exercises – …
