For comparing the $e.m.f.$'s of two cells with a potentiometer, a standard cell is used to develop a potential gradient along the wires. Which of the following possibilities would make the experiment unsuccessful
AThe $e.m.f.$ of the standard cell is larger than the $E$ $e.m.f.$'s of the two cells
B
The diameter of the wires is the same and uniform throughout
C
The number of wires is ten
DThe $e.m.f.$ of the standard cell is smaller than the $e.m.f.$'s of the two cells
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DThe $e.m.f.$ of the standard cell is smaller than the $e.m.f.$'s of the two cells
d (d) The emf of the standard cell must be greater than that of experimental cells, otherwise balance point is not obtained.
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