Q. If the force exerted by an electric dipole on a charge q at a distance of 1 m is F, the force at a point 2 m away in the same direction will be
A) $\frac{F}{2}$
B) $\frac{F}{4}$
C) $\frac{F}{6}$
D) $\frac{F}{8}$
Explanation
(d) Force exerted by an electric dipole on a charge is inversely proportional to the cube of distance of the charge from the centre of the dipole
$F \propto \frac{1}{r^{3}}$
$\therefore\ \frac{F}{F^{'}} = \left( \frac{r^{'}}{r} \right)^{3}$
$\frac{F}{F^{'}} = \left( \frac{2}{1} \right)^{3}$
$F^{'} = \frac{F}{8}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.