Three point charges +q, −q and +q are placed at points (x = 0, y = a, z = 0),(x = 0, y = 0, z = 0) and (x = a, y = 0, z = 0) respectively. The magnitude and direction of the electric dipole moment vector of this charge assembly are ?

Three point charges +q, −q and +q are placed at points (x = 0, y = a, z = 0),(x = 0, y = 0, z = 0) and (x = a, y = 0, z = 0) respectively. The magnitude and direction of the electric dipole moment vector of this charge assembly are ?

(a) \( \sqrt{2}qa \) along the line joining points \( (x = 0, y = 0, z = 0) \) and \( (x = a, y = a, z = 0) \)

(b) \( qa \) along the line joining points \( (x = 0, y = 0, z = 0) \) and \( (x = a, y = a, z = 0) \)

(c) \( \sqrt{2}qa \) along +ve \( x \) direction

(d) \( \sqrt{2}qa \) along +ve \( y \) direction

Answer :  (a) \( \sqrt{2}qa \) along the line joining points \( (x = 0, y = 0, z = 0) \) and \( (x = a, y = a, z = 0) \)

\( p = 2qa \)

\( \vec{P}_{\text{resultant}} = \sqrt{2} \, \vec{P} = \sqrt{2} \cdot (q a) \)