Question

Three points charges $+q,-2q$ and $+q$ are placed at points $(0,1,0),(0,0,0)$ and $(1,0,0)$ respectively. The magnitude and direction of the resultant electric dipole moment vector of this charge assembly will be :

• A. $\sqrt{2}q$ along X axis
• B. $\sqrt{2}q$ along Y axis
• C. $\sqrt{2}q$ along the line joining points $(0,0,0)$ and $(1,1,0)$
• D. $q$ along the line joining the points $(0,0,0)$ and $(1,1,0)$

Answer 1

The correct option is C $\sqrt{2}q$ along the line joining points $(0,0,0)$ and $(1,1,0)$

The direction of the electric dipole is from negative charge to positive charge.

Since the negative charge is placed at the origin and two charges are place at equal distance along both axis.

The resultant dipole will be along the resultant of these two vectors positioned at$\left(a,a,0\right)$

$OR=\sqrt{q{a}^2+q{a}^2}$

Hence the magnitude of the resultant electric dipole is$\sqrt{2}qa$