To measure the internal resistance of a battery, potentiometer is used. For R = 10Ω , the balance point is observed at l = 500 cm and for R = 1Ω the balance point is observed at l = 400 cm . The inter

Question

To measure the internal resistance of a battery, potentiometer is used. For R = 10Ω , the balance point is observed at l = 500 cm and for R = 1Ω the balance point is observed at l = 400 cm . The internal resistance of the battery is approximately :

TestHub · Accepted Answer

Let potential gradient be λ . ​ ∴ i × 10 = λ × 500 = ε − ir s ​ ⇒ 500 λ = ε − 50 λ r s ​ ​ Also, ​ i ′ × 1 = λ × 400 = ε − i ′ r s ​ ⇒ 400 λ = ε − 400 λ r 5 ​ ∴ 100 λ = 350 λ r s ​ ⇒ r s ​ = 35 10 ​ ≈ 0.3Ω ​

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