Q. 63.7( 3 Votes )
An electric dipole is placed in an electric field generated by a point charge.
A. The net electric force on the dipole must be zero.
B. The net electric force on the dipole may be zero.
C. The torque on the dipole due to the field must be zero.
D. The torque on the dipole due to the field may be zero.
The field due a point charge is always radial (radially outwards for positive charge and radially inwards for negative charge). A dipole placed in that electric field will never feel equal and opposite forces due to the radial nature of the field. Therefore, option (a) and (b) are incorrect.
Torque on the dipole may be zero in the case when the dipole is placed along the electric field (as in that only case, and will be parallel or antiparallel, thus torque will be zero.)
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A. Derive the expression for electric field at a point on the equatorial line of an electric dipole.
B. Depict the orientation of the dipole in (i) stable, (ii) unstable equilibrium in a uniform electric field.
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