An electric dipole is placed in a uniform electric field. The net electric force on the dipole
A. is always zero
B. depends on the orientation of the dipole
C. can never be zero
D. depends on the strength of the dipole
An electric dipole consists of equal and opposite charges placed at some distance.
The dipole moment of this configuration is given as p=q(2a)
When the dipole is kept in an external electric field E, both its charges experience some force. Let the force on the positive charge(q) and negative charge(-q) be FP and FN respectively.
Therefore, FP =qE and FN =-qE.
I.e. FP =- FN
that is force on the dipole is equal in magnitude but opposite in direction irrespective of its orientation.
Therefore, force on an electric dipole placed in an electric field is always zero.
Rate this question :
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.
Physics - Board Papers
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