An electric dipole is placed at an angle of 30° with an electric field of intensity $2 imes 10^5 N

Question

An electric dipole is placed at an angle of 30° with an electric field of intensity $2 	imes 10^5 N/C$ It experiences a torque equal to 4 Nm. Calculate the charge on the dipole if the dipole length is 2cm

Professor PC Thomas Classes · Answer

Torque $τ = pE\sin	heta$. So $p = \frac{τ}{E\sin	heta} = \frac{4}{2 	imes 10^5 	imes \sin 30°} = \frac{4}{2 	imes 10^5 	imes 0.5} = \frac{4}{10^5} = 4 	imes 10^{-5}$. Since $p = qd$, $q = \frac{p}{d} = \frac{4 	imes 10^{-5}}{2 	imes 10^{-2}} = 2 	imes 10^{-3} = 2$ mC.