WBJEE · Physics · Electrostatics
Two charges \(+q\) and \(-q\) are placed at a distance \(a\) in a uniform electric fleld. The dipole moment of the combination is \(2 q a(\cos \theta i+\sin \theta)\). where, \(\theta\) is the angle between the direction of the field and the line joining the two charges. Which of the following statement(s) is/ase correct?
- A The torque exerted by the field on the dipole vanishes
- B The net force on the dipole vanishes
- C The torque is independent of the choice of coordinates
- D The net force is independent of a
Answer & Solution
Correct Answer
(D) The net force is independent of a
Step-by-step Solution
Detailed explanation
The situation can be diagrammatically as, The dipole moment, \[ \mathbf{P}=2 q a(\cos \theta \hat{\mathbf{i}}+\sin \theta \hat{\mathbf{j}}) \] The net force on the dipole is always zero while net torque on the dipole is not zero.
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