# Dipole in an external electric field

• Prashasti

## Homework Statement

Why isn't the expression for torque on a dipole kept in an external electric field ExP? Why is it PxE?
No such indication has been given in any of the derivations, that it is mandatory for it to be PxE, so why can't it be ExP?

2. The attempt at a solution
Is it all about experiments?

## Homework Statement

Why isn't the expression for torque on a dipole kept in an external electric field ExP? Why is it PxE?
No such indication has been given in any of the derivations, that it is mandatory for it to be PxE, so why can't it be ExP?

2. The attempt at a solution
Is it all about experiments?
What's the essential difference in the cross products A x B versus B x A?

The direction of the resultant of A x B is just opposite to that of B x A...

The direction of the resultant of A x B is just opposite to that of B x A...
Right. So it comes down to the definitions of positive or negative directions for quantities in the chosen coordinate system. This includes assumed directions for positive or negative torques, angular velocities, etc., which are vector quantities (or pseudo vector quantities in some cases, but that's another topic).