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A uniform wire of length 4 m and resista...

A uniform wire of length 4 m and resistance `2Omega`. is connected as potentiometer in series to a battery of emi 5 V arid an external resistance of `3 Omega`. When using a cell of EMF E, the balancing length is found to be 2.5 m, Find the potential gradient along the potentiometer wire and the value of E.

Text Solution

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(a) Current in `AB = 5/5 = 1 A`
Potential drop across `AB= 2 xx 1 = 2V`
Potential gradient `=2/400 = 0.005 V//cm`
(b) `E = kl = .005 xx 250 = 1.25 V`
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