16 As seen in the last chapter, in a uniform electric field,
the dipole experiences no net force; but experiences a
torque t t t t t given by
t = 
t = 
t = 
t = 
t = p × E
(2 30)
which will tend to rotate it (unless p is parallel or
antiparallel to E) Suppose an external torque tttttext is
applied in such a manner that it just neutralises this
torque and rotates it in the plane of paper from angle q0
to angle q1 at an infinitesimal angular speed and without
angular acceleration