Force and torque on a sphere with electric dipole moment moving in a dielectric fluid in the presence of a uniform magnetic field

The torque exerted by a magnetic field on a sphere with permanent electric dipole moment moving steadily in a dielectric fluid is calculated to lowest order in the dipole moment. Hence the force exerted on a steadily rotating sphere with electric dipole moment is found by Onsager symmetry. The modif ication from the vacuum values of torque and force depends only on the slip parameter and the static dielectric constant of the fluid. It is suggested that for a macroscopic ferro electric sphere the calculated effects could be measured experimentally without great difficulty. (C) 2000 Elsevier Scie nce B.V. All rights reserved.