# The emf of a cell is balanced by a length of 120 cm of a potentiometer wire. When the cell is shunted by a resistance of 10 Ω, - Physics

Sum

The emf of a cell is balanced by a length of 120 cm of a potentiometer wire. When the cell is shunted by a resistance of 10 Ω, the balancing length is reduced by 20 cm. Find the internal resistance of the cell.

#### Solution

Data: R = 10 Ω, l1 =120 cm,l2 = 120 - 20 = 100 cm

r = "R"(("l"_1 - "l"_2)/"l"_2)

= 10 ((120 - 100)/100)

= 2 Ω

The internal resistance of the cell is 2 Ω.

Concept: Potentiometer
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