The length of a wire of a potentiometer is … …, and the … … … of its standard cell is … volt. It is employed to measure the … of a battery whose internal resistance in … If the balance point is obtained at … … from the positive end, the … of the battery is where … is the current in the potentiometer wire.

Option D. Potential gradient along wire, K = … volt/cm

Current Electricity

JEE Main 2003 · Annual, Paper 1 · Q6499

PhysicsMedium226×since 2002Q6499

The length of a wire of a potentiometer is

100

cm

, and the

e.

m.

f.

of its standard cell is

E

volt. It is employed to measure the

e.m.f.

of a battery whose internal resistance in

0.5\Omega .

If the balance point is obtained at

1=30

cm

from the positive end, the

e.m.f.

of the battery is where

i

is the current in the potentiometer wire.