In a potentiometer experiment, the balancing length of a cell is 560 cm . When an external resistance of 10Ω is connected in parallel to the cell, the balancing length changes by 60 cm . The internal

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In a potentiometer experiment, the balancing length of a cell is 560 cm . When an external resistance of 10Ω is connected in parallel to the cell, the balancing length changes by 60 cm . The internal resistance of a cell is

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Let us Consider a cell of emf E and balancing length 1 1 ​ E = kl 1 ​ potential difference is balanced by length l 2 ​ . V = kl 2 ​ Internal resistance of the cell r = ( V E − V ​ ) R = ( V E ​ − 1 ) R = ( l 2 ​ l 1 ​ ​ − 1 ) R = ( 560 − 60 560 ​ − 1 ) 10 = ( 50 56 ​ − 1 ) 10 = 5 6 ​ = 1.2Ω ​

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