Consider an electric dipole comprising two charges +q and -q each with mass m, separated by a fixed distance d and initially at rest with its dipole moment pointing along î. A uniform electric field Eĵ is turned on at time t = 0 and it is turned off at t = t(f), when the dipole moment makes an angle θ(f) with î. Neglecting any sources of energy loss, correct option(s) is/are:
Select all that apply

Question

Consider an electric dipole comprising two charges +q and -q each with mass m, separated by a fixed distance d and initially at rest with its dipole moment pointing along î. A uniform electric field Eĵ is turned on at time t = 0 and it is turned off at t = t(f), when the dipole moment makes an angle θ(f) with î. Neglecting any sources of energy loss, correct option(s) is/are:

Select all that apply

G1 Physics · Accepted Answer

The net force on an ideal dipole in a uniform electric field is zero, so the center of mass is not deflected; A is false. The electric torque changes the rotational kinetic energy according to ΔK = pE sinθ(f), with p = qd. Using I = md²/2 for the two masses gives the relation between ω(f) and θ(f), leading to option B in the official accepted key. Once the field is switched off, torque becomes zero and the dipole continues with constant angular velocity, so D is correct. The source key lists 'BD or D'; this workbook records B,D.