In an experiment to measure the internal resistance of a cell by potentiometer, it is found that the balance point is at a length of 2 m when the cell is shunted by a 4 Ω resistance and at 3 m when cell is shunted by a 8 Ω resistance. The internal resistance of cell is -

Question

In an experiment to measure the internal resistance of a cell by potentiometer, it is found that the balance point is at a length of 2 m when the cell is shunted by a 4 Ω resistance and at 3 m when cell is shunted by a 8 Ω resistance. The internal resistance of cell is -, 12 Ω, 8 Ω, 16 Ω, 1 Ω

MARKS App · Accepted Answer

V A - V B = ϕ × l E - E r r + 4 = ϕ × 2 ....(i). E 4 r + 4 = ϕ × 2 .... (i) Similarly, E 8 r + 8 = ϕ × 3 ....(ii) e q 1 e q 2 ⇒ r + 8 2 r + 4 = 2 3 ⇒ 3 r + 24 = 4 r + 16 ⇒ r = 8 Ω

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