An electric dipole with moment p = 2 × 10⁻⁹ C·m is in a uniform electric field of 10⁵ N/C at 90° to the field. The torque on the dipole is:
Correct answer: A. 2 × 10⁻⁴ N·m
- A. 2 × 10⁻⁴ N·m
- B. 1 × 10⁻⁴ N·m
- C. Zero
- D. 4 × 10⁻⁴ N·m
Explanation
Torque on a dipole is τ = pE sinθ, where p = 2 × 10⁻⁹ C·m, E = 10⁵ N/C, and θ = 90° (sin 90° = 1). Thus, τ = (2 × 10⁻⁹)(10⁵) = 2 × 10⁻⁴ N·m.
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