Dipole moment: An ideal electric dipole moment is a pair of equal and opposite c
ID: 1269935 • Letter: D
Question
Dipole moment: An ideal electric dipole moment is a pair of equal and opposite charges +q and -q separated by a distance The "dipole moment" of the pair is a vector p defined where r is the displacement vector from the negative to the positive charge. The magnitude of the dipole moment is qa. Force on a dipole: Consider a dipole moment immersed in a uniform electric field E. What is the force on the dipole? Torque on a dipole: Assume the negative charge is at the origin and the position of the positive charge is r. Assume that the dipole is immersed in a uniform electric field E. What is the torque on the dipole? Electrostatic Energy: Again assume that the negative charge is at the origin and the position of the positive charge is (x,y,z). Assume that the dipole is in an electric field of magnitude E that points along the 2-axis. Thus E = Ek. What is the potential energy of the dipole? [Hint: Recall that for a charge Q at position (x, y, z) in a uniform electric field Ek the electrostatic energy is .Explanation / Answer
b) force on positive charge =qE
force on negative charge = -qE
net force=qE-qE=0
c)torque on a dipole = rFsina where a=angle between r and force
=rqEsina
=pEsina (qr=p)
d) potential energy= -pEcosa where a is angle between p and E
=-qErcosa