Practice question

Given: In an LCR circuit with R = 3 Ω, X_L = 8 Ω, X_C = 4 Ω, what is the power factor? These values define the system as per NCERT data. Formula: Impedance: Z = sqrtR² + (X_L - X_C)² = sqrt3² + (8 - 4)² = sqrt9 + 16 = 5 Ω. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Power factor: cos phi = R/Z = 3/5 = 0.6 . 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.