Practice question

Given: A circuit has a 20 V battery with 2 Ω internal resistance and three resistors 5 Ω, 10 Ω, 20 Ω in parallel. What is the current through the 10 Ω resistor? These values define the system as per NCERT data. Formula: Parallel resistance: 1/R_p = 1/5 + 1/10 + 1/20 = 4 + 2 + 1/20 = 7/20 Rightarrow R_p = 20/7 approx 2.86 Ω. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Total resistance: R_{total = 2 + 2.86 = 4.86 Ω . Total current: I = fracvarepsilonR_{total = 20/4.86 approx 4.12 A . Voltage across parallel: V = I R_p = 4.12 × 2.86 approx 11.78 V . Current through 10 Ω : I_{10 = V/10 = 11.78/10 approx 1.18 A . 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.