Practice question

Given: A dipole p = 6 × 10⁻⁹ C m is rotated from θ = 0° to 90° in a field E = 3 × 10⁵ N/C . What is the work done? These values define the system as per NCERT data. Formula: Work done: W = p E (cos θ_0 - cos θ_1) = 6 × 10⁻⁹ × 3 × 10⁵ × (cos 0° - cos 90°). This is the standard NCERT relation for this phenomenon. Substitution & Calculation: W = 6 × 10⁻⁹ × 3 × 10⁵ × (1 - 0) = 1.8 × 10⁻³ J . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.