Electric Dipole in Uniform Field?

📌 CONCEPT: An electric dipole placed in a uniform electric field experiences a torque that tends to align the dipole moment with the direction of the field, resulting in a stable configuration when the dipole is fully aligned.

📐 RULE / FORMULA: The torque (τ) acting on a dipole in a uniform electric field (E) is given by τ = pE sinθ, where p is the dipole moment and θ is the angle between the dipole moment and the field direction.

💡 WORKED EXAMPLE: Given p = 10^-9 C-m and E = 10^4 N/C, we can calculate the torque acting on the dipole for different angles θ. For θ = 0°, τ = 0, indicating no torque. For θ = 90°, τ = pE, and for θ = 180°, τ = -pE. The dipole aligns with the field when the torque is maximum, i.e., at θ = 90°.

⚠️ COMMON MISTAKE: Students often mistake the torque acting on a dipole in a uniform field to be maximum when θ = 0°, whereas it is maximum when θ = 90°, resulting in the dipole aligning with the field.