Current Electricity and Electrical InstrumentHard
Question
In the given potentiometer circuit, the resistance of the potentiometer wire AB is R0. C is a cell of internal resistance r. The galvanometer G does not give zero deflection for position of the jockey J. Which of the following cannot be a reason be a reason for this ?


Options
A. r > R0
B. R > > R0
C.Emf of C > emf of D
D.The negative terminal of C is connected to A
Solution

If e.m.f of c is greater than the e.m.f of the ′D′
I = 0
So r does not play any role of zero deflection in galvanometer.
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