An electric dipole, consisting of two opposite charges of 2 × 10−6C each separated by a distance 3 cm is placed in an electric field of 2 × 105 N/C. Torque acting on the dipole is ?

An electric dipole, consisting of two opposite charges of 2 × 10−6C each separated by a distance 3 cm is placed in an electric field of 2 × 105 N/C. Torque acting on the dipole is ?

(a) \( 12 \times 10^{-1} \, \text{N·m} \)

(b) \( 12 \times 10^{-2} \, \text{N·m} \)

(c) \( 12 \times 10^{-3} \, \text{N·m} \)

(d) \( 12 \times 10^{-4} \, \text{N·m} \)

Answer :  (c) \( 12 \times 10^{-3} \, \text{N·m} \)

\( \tau = \vec{p} \times \vec{E} \)

\( \tau = q \cdot 2l \cdot E \cdot \sin\theta \)

\( \tau = 2 \times 10^{-6} \cdot (3 \, \text{cm}) \cdot 2 \times 10^5 \)

\( \tau = \text{(c)} \; 12 \times 10^{-3} \, \text{N·m} \)