Q. 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. (iii) cell p is replaced by another cell whose emf is lower than that of cell Q.

Dear Student,

ilength of the null point be x. let the resitance of potentiometre wire be rQ=PR+rxlrso from the if everything is kept constant and R changes x is directly proportional to Rhence if R increased then x will also increased that is null point will shift forward.iithe value of x is independent of the value of s the resistance with Qiiiif thevalue of Q is lowered then from the above eqn x is directly proportional to Qhence if Q is decraesed then x will also lowered and shift backward

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