Saved Bookmarks
| 1. |
Two small identical electric dipoles AB and CD, each of dioplemomentp are kept at an angleof 120^(@) as shown in Figure. What is the resultant dipolemoment of this combination ? If this system is subjectedto electricfield vec((E)) directed along + X direction, what will be the magnitude and direction of the torque actingon this ? |
|
Answer» SOLUTION :In FIG. two dipolemoments `p_(1)` alongBA and `p_(2)` along DC ACT at an angleof `120^(@)`. The resultant dipole moment is along OR `P_(R) = sqrt(p_(1)^(2) +p_(2)^(2) + 2p_(1) p_(2) cos 120^(@))` `= sqrt(p^(2) + p^(2) + 2pp (- (1)/(2))) = p` As `/_AQR = 60^(@)`, therefore, `/_XQR = theta = 90^(@) - 60^(@) = 30^(@)` `tau = pE sin theta = pE sin 30^(@) = pE//2` The direction of torque is perpendicular to `VEC(p) and vec(E) , i..e.,` perpendicular to planeof paper and outwards, Fig. 
|
|