Electric dipole in a uniform electric field

[logearav]

Homework Statement

An electric dipole placed in a uniform electric field experiences a torque which tends to align the dipole parallel to the field. At the same time, due to two equal and unlike parallel forces Eq and -Eq acting at q and -q, the net force is zero. When the net force is zero, how the dipole moves parallel to the field? Please help members.

Homework Equations

The Attempt at a Solution

 

[tiny-tim]

hi logearav!

An electric dipole placed in a uniform electric field experiences a torque which tends to align the dipole parallel to the field. At the same time, due to two equal and unlike parallel forces Eq and -Eq acting at q and -q, the net force is zero. When the net force is zero, how the dipole moves parallel to the field?

a torque (a couple) is a net force of zero …

when the dipole is at an angle to the E field, the field pulls the opposite charges in opposite but parallel directions, and that turns the dipole

(and since the field is uniform, the forces are equal in magnitude, and the centre of mass stays where it is)

 

[logearav]

Mr. tiny-tim, thanks a lot for the explanation.