Explore BrainMass

# Electrostatics - Electric dipole

Not what you're looking for? Search our solutions OR ask your own Custom question.

This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

For two equal in magnitude but opposite charges +Q and -Q we can define a vector of dipole moment p, with the magnitude absolute value (p)=dxQ, where d is the distance between the charges. The direction of p is the direction from negative to positve charge (see figure)

1.)What force acts on the dipole in a uniform electric field E.

2.)What torque is acting on the dipole.

https://brainmass.com/physics/torques/electrostatics-electric-dipole-218014

## SOLUTION This solution is FREE courtesy of BrainMass!

+Q F

p d dsinÎ¸ E
Î¸
- F -Q

A +ve charge experiences a force in the direction of the electric field vector E and -ve charge opposite to it. Hence, the forces acting on the charges of the dipole are as shown in the fig..

Magnitude of force on each charge = F = QE (Because by definition electric field intensity at a point is the force experienced by a unit positive charge placed at that point. Hence, force experienced by a charge Q placed at that point is QE)

1) Net force acting on the dipole = 0 (as forces F and -F cancel out).

2) Torque acting on the dipole = Ï„ = Force x Perpendicular distance between the line of action of the forces = QE x dsinÎ¸ = (Qd)EsinÎ¸ = pEsinÎ¸

Ï„ = pEsinÎ¸

In vector form : Ï„ = p X E (cross product of vectors p and E)

This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!