1. Dustin_Whitelock
Why is the most stability obtained by a dipole in a magnetic field or an electrostatic field always is at parallel position with the field and most unstable at anti parallel position? The potential energy is 0 at angle =90 degrees. Why isn't that position the most stable?
Definition of an ELECTRIC dipole moment in terms of its VECTOR direction.
Notice that the vector dipole moment is in the OPPOSITE sense to the direction of the electric field.
Stable/neutral equilibrium
A vector dipole
A vector electrostatic field
Like charges repel; unlike charges attract

2. Unstable situation
Turned
A vector dipole
Turned
A vector electrostatic field
Like charges repel; unlike charges attract
Ok, so what’s the definition of dipole moment, in terms of the vector. Is it FROM plus TO minus, or is it from MINUS to PLUS ...

3. Unstable situation
A vector dipole
Pushed away
Pushed away
A vector electrostatic field
Like charges repel; unlike charges attract