# Torque in electric fields

5+ Year Member
I'm trying but I really don't get the concept. Is this tested commonly on the MCAT? If so, would someone be so kind as to explain it to me? Thanks

#### lorenzomicron

I'm trying but I really don't get the concept. Is this tested commonly on the MCAT? If so, would someone be so kind as to explain it to me? Thanks
Hi, I'm not sure that its tested commonly.

But, I can tell you that torque in magnetic fields is encountered when some object has an electric dipole, i.e. uneven distribution of charge on the object. Then, a force called torque or electric dipole moment will be produced, in the same way as the mechanic torque, i.e. rxE, where r is the vector of the electric dipole and E is the vector field of the electric field.

an important application of this is seen in polar molecules, which can be caused to rotate and such because torque is produced in an electric field since these possess dipoles.

#### UC pre med

10+ Year Member
5+ Year Member
This is an effect that can happen in a variety of instances. The first and most prominent one is the torque on a dipole, which is a positive and negative charge close to each other. Since the chares are opposite, in the prescence of an electric field, they will experience opposite forces and create a net torque. The dipole will always want to align itself with the electric field so that the forces cancel out and there is no longer any torque. The formula for this is :

T= p X E , torque equals the diople moment cross product Electric field vector.

The next common example is the torque produced on a current loop in the presense of a MAGNETIC field, but I dont know if you want to know that as it gets pretty complex. If you want me to explain then just pm me or ask again. Hope this helped. Wish i had some diagrams to show you but sadly i dont have the time.