# TTwo small identical dipoles AB and CD,each of dipole moent p are kept at an anglre of 120 degree ai in figure.What is the resultant dipole of this combination?If this system is subjected to electric field(E) directed along +x axis what will be the magnitude and direction of torque acting on this?

### Asked by Rajeev | 12th May, 2015, 03:17: PM

Expert Answer:

### The two dipoles are placed at an angle 120°.
The dipole moment of AB is directed towards B and that of CD is directed towards C.
Hence, the resultant dipole moment is given as
When the system is subject to an electric field, there is a torque acting on the dipoles.
The field is directed towards X-axis. The angle COR in the above diagram will be 60°.
Hence, the angle between the resultant dipole moment and electric field is 90 - 60 = 30°.

Therefore, the torque on the system is
The direction of torque is perpendicular to both p and E.

### Answered by Romal Bhansali | 12th May, 2015, 06:00: PM

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