A $10 \,m$ long potentiometer wire is connected to a battery having a steady voltage. A Leclanche cell is balanced at $4 \,m$ length of the wire. If the length is kept the same, but its cross-section is doubled, the null point will be obtained at ........... $m$
A$8$
B$4$
C$2$
D
None of these
Easy
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B$4$
b (b)
If length is kept same, potential gradient remains same, so null point does not change.
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