Q In the potentiometer circuit shown, the null point is at X State with reason, where the balance - Physics - Current Electricity

Question

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

Shobhit Mittal · Accepted Answer

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