Question

an electric dipole of dipole moment 2×10^-6 cm is kept in a uniform electric field of 0.5 N/C. it is rotated through an angle of 30° find the torque expressed by it​

Answer 1

Explanation:

Torque that E exerts on p is τ=p×E

∴τ=(2.0i+3.0j)10−6×(3.0i+2.0k)105Nm=(6i−4j−9k)×10−1Nm=(0.6i−0.4j−0.9k)Nm

Potential Energy of the dipole =−p.E=−(6+0+0)×10−1=−0.6 Joules 

Maximum Potential energy is when the dipole is rotated by 180 o , which is 2p.E=2.4J