QUESTION 2.1 Torque on an electric dipole in a uniform electrostatic eld. An ele
ID: 1660980 • Letter: Q
Question
QUESTION 2.1 Torque on an electric dipole in a uniform electrostatic eld. An electric dipole, with charges Q and -Q, is placed in a uniform electrostatic field, whose intensity vector is E, as shown in Fig.Q2.1. The field exerts a torque on the dipole for (A) cases (b) and (d) only (B) case (c) only (C) cases (b), (c), and (d) only (D) cases (a) and (e) only (E) cases (a), (b), (d), and (e) only. (F) none of the cases shown -g -0 Figure Q2.1 Electric dipole in a uniform electrostatic field of intensity E - five different positions of the dipole relative to the field lines; for Question 2.1.Explanation / Answer
Answer = c that is b, c, d only.
The formula for torque is.
Torque = integral(FxR)
So from the equation either the force should be perpendicular to the distance between dipole or any component of the dipole pairs.
Here in part a and e, dipole moment of system is parallel to electric field which exert force on system. So cross product of F and r will be vanish. So no torque
In part b and d, the angle is 90 degree. So torque will exist.
In part c the component of dipole perpendicular to electric field will exert torque.