Worked example: A water molecule has dipole moment p = 6.2 × 10⁻³⁰ C·m. (a) Find the torque on it in a uniform field E = 3.0 × 10⁶ N/C when p makes 60° with E. (b) Where is the torque maximum? Step 1: τ = pE·sinθ = (6.2 × 10⁻³⁰)(3.0 × 10⁶)(sin60°) = (1.86 × 10⁻²³)(0.866) ≈ 1.61 × 10⁻²³ N·m. Step 2: This tiny torque acts on a single molecule; in a microwave, the field oscillates billions of times per second, and the molecule's constant rotational struggle becomes heat. Step 3: Torque is maximum at θ = 90° (sinθ = 1): τ_max = pE ≈ 1.86 × 10⁻²³ N·m, and zero at θ = 0° and 180° (aligned or anti-aligned — the latter is unstable equilibrium). Note the net force is zero in the uniform field; only rotation occurs.