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Electric Field with a dipole
1. A dipole, with charges +/- 9e has an electric dipole moment of 7.3E-30 Cm. The
dipole is placed in an external electric field of magnitude 1.9E4 N/C.
a. How far apart of the two charges?
b. What is the maximum torque that the external field can exert?
c. How much work must the field do to turn the dipole end to end (0 to 180)?
2. An electric dipole with charges of +/- 1.5E-9C is separated by 6.2E-6m and placed in
an electric field of strength 1100 N/C.
a. What is the magnitude of the electric dipole moment?
b. What is the difference in potential energy corresponding to dipoles oriented
parallel and antiparallel to the electric field?
3. An electric dipole consists of charges +/-2e and has a separation of 7.8E-10m. It is
placed in an electric field of magnitude 3.4E6 N/C. Calculate the magnitude of the
torque on the dipole when the dipole moment is
a. parallel
b. perpendicular
c. opposite
to the electric field.
4. An external electric field has a field intensity of 1.6E6 N/C East. A dipole is sent
through this field. It has a dipole moment of 3E-24 Cm and it each sphere of the
dipole has charge of 1E-12 C.
a. What is the force the field applies on each charge?
b. To obtain a maximum torque value, what direction is the dipole moment.
c. At this angle, what is the torque?
d. What is the potential energy of the dipole when the electric dipole moment is
(a) in the same direction as the E field
(b) in the opposite direction of the E field
(c) perpendicular to the E field
5. A force of 15.6 N is applied by an external electric field on a dipole with 3C charge.
a. What is the magnitude of this electric field?
b. If the dipole were 1E-7 m in distance, what is the dipole moment?
c. How much torque does this dipole experience if its dipole moment makes a 45
degree angle with the E field?
d. What is the potential energy at this point?
6. A dipole of charge 12e has a dipole moment of 6E-29 Cm.
a. How far apart are these charges?
b. If this dipole is placed in an electric field with field intensity of 7.7E5 N/C, what
is the maximum torque it will experience?
c. What is the linear acceleration of the dipole due to this external electric field?
d. How much work is done to move this charge from its position of maximum torque
to that of where in which the angle between the dipole moment and the Electric
field is 180 degrees?