Question

There are two possible alignments of a dipole in an external electric field where the dipole is in equilibrium:

1. Draw a field diagram for a uniform electric field and show these two allignments

2.Are both allignments stable? (consider what would happen in each case if you gave the dipole a slight twist)

3. Based on your answer to part 2, and your experiance in mechanics, in which orientation does the dipole have less potential energy?

Are both alignments stable?

(

Consider what would happen in each case if you gave the dipole a slight twist.) In which orientation does the dipole have less potential energy?

Answer 1

equillibrium means net force = 0

in a dipole there are +ve and -ve charges which experiences force in opposite directions So to get net force = 0 \

orientation will be like foll.

stable equillibrium is when +q is in right of -q

because if we slightly rotate this orientation force on +q will be rightwards and on -q will be leftwards so it will orient again in same configuration

But if orientaion is like

then if we give dipole a slight twist force on -q will be in left and force on +q wil be right

that will make it rotate hence it is not stable

Potential energy of a system is minimum when system is stable

so in 1st case it was minimum