# Homework Help: Which way will the dipole rotate ? ClockWise or Counter Clockwise?& Magnetic moment

1. Jul 10, 2012

### nishantve1

This is not a homework question I encountered this while revisiting the Electric Dipoles .
First of all if someone explains me why the dipole

So in the image above which way should the dipole rotate ? Anti Clock Wise or Clock Wise .
What My intuition says is the Energy of a dipole is
U = -p.E
Which is -pEcosθ
So the Energy Graph would be

So theres a Stable Equilibrium at 0 and unstable equilibrium at ∏

So what I know is that angle is angle made between the E field and the Dipole moment .
What I am not getting is which way is the angle measured ? So if I rotate the dipole moment all the way to bottom will the angle still be same ? Like in the figure ?

Also still which way the dipole rotate it seems easier for it rotate counter clockwise . But Will it ?

2. Jul 10, 2012

### Redbelly98

Staff Emeritus
Re: Which way will the dipole rotate ? ClockWise or Counter Clockwise?& Magnetic mome

To get the angle, you need to know which way the dipole vector p is directed, and compare that direction with the direction of E.

Alternatively, you could draw force vectors on the (+) and (-) charges, and from that figure out in what direction the net torque is acting.