An electric dipole will be in stable equilibrium if the angle between the axis of the dipole and the electric field is ________
A. 0 degree
B. 180 degree
C. 90 degree
D. 45 degree
Answer:A
An electric dipole will be in stable equilibrium if the angle between the axis of the dipole and the electric field is ________
A. 0 degree B. 180 degree C. 90 degree D. 45 degree
Explanation: Torque acting on a dipole is p*E*sinθ where E is the electric field. Now θ is 0 degree, so sinθ becomes 0 and hence no torque acts on the dipole. So in this case, no force or torque acts on the dipole. Therefore it will be the condition of stable equilibrium. In the case of θ=180 degree, sinθ is also 0 but the condition is known as unstable equilibrium i.e. if we rotate the dipole a bit, it will not come back to its initial position.