Question

In an electric dipole, aren't the forces equal and opposite and thus they should be in stable equilibrium? they why is their a torque when it is placed in an electric field?

Answer 1

Net force = 0 is a necessary condition for equilibrium, but it is not a sufficient one.

If those two opposite forces are not aligned, then the resulting couple will rotate the body until they are.

Answer 2

can you explain how exactly a couple is formed? I just don't understand.

Answer 3

Definition of a couple is any system of forces with net force 0 and net moment non zero.

The simplest example is 2 opposite forces (hence the name 'couple') whose lines of actions are not aligned.

Answer 4

Thank you, that really helped. :)