In a potentiometer, the null point is received at $7^{th}$ wire. If now we have to change the null point at $9^{th}$ wire, what should we do ?
A
Increase resistance in series with applied emf
B
Increase resistance in main circuit
C
Decrease resistance in main circuit
D
Decrease applied emf
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B
Increase resistance in main circuit
b To shift the balance point on higher length, the potential gradient of the wire is to be decreased. The same can be obtained by decreasing the current of the main circuit, which is possible by increasing the resistance in series of potential wire
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