In the circuit shown in the Figure, cell is ideal and R₂ = 100 Ω. A voltmeter of internal resistance 200 Ω reads V₁₂ = 4 V and V₂₃ = 6 V between the pair of points 1-2 and 2-3 respectively. What will be the reading of the voltmeter between the points 1-3?

Question

G1 Physics · Accepted Answer

Image When measuring V₂₃, the 200 Ω voltmeter is in parallel with R₂ = 100 Ω, so the loaded equivalent is 200/3 Ω. From 6 V, circuit current is 0.09 A. For the V₁₂ measurement, use 4 V and the same source emf relation to determine R₁, then connect the voltmeter across 1-3. The resulting reading is 12 V.