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## Torque on a Dipole in a Uniform Electric Field A dipole is kept in a uniform electric field making an angle θ with the field. **Diagram** A horizontal line represents the electric field. A dipole is drawn along the line with the positive charge on the right and the negative charge on the left....

## Torque on a Dipole in a Uniform Electric Field A dipole is kept in a uniform electric field making an angle θ with the field. **Diagram** A horizontal line represents the electric field. A dipole is drawn along the line with the positive charge on the right and the negative charge on the left. The angle between the dipole and the electric field is θ. **Vectors** * **Electric field (E):** This is a vector pointing to the right and labeled "E". * **Distance between the charges (2l):** This is a vector pointing to the right and labeled "2l". * **Force on the positive charge (F+q):** This is a vector pointing to the right and labeled "+qE". * **Force on the negative charge (F-q):** This is a vector pointing to the left and labeled "-qE". **Net Force** * The net force on the dipole is 0. Since the forces on the positive and negative charges are equal in magnitude and opposite in direction, they cancel each other out. **Torque Couple of Force and Opposite Force acting at Two Different Points** **Create a Torque** * **τ = F x r** * **τ = qE x 2l sin θ** * **τ = pE sin θ** Where: * τ is the torque * qE is the force on each charge * 2l is the distance between the charges * p is the dipole moment (p = q x 2l) ---