Q10 of 26 Page 1

In the potentiometer circuit shown, the null point is at X. State with reason, where the balance point will be shifted when

(a)resistance R is increased, keeping all other parameters unchanged;


(b) resistance S is increased, keeping R constant.



(a) As the resistance R increases, the current through the wire decreases. Hence, the potential difference across AX will also decrease. To counter it, the resistance will have to increase and the null point will shift towards B.


(b) Here, the terminal potential difference decreases as S increases. Hence, the balance point will shift towards A.


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