The emf of a battery A is balanced by a length 75 cm on a potentiometer wire. The emf of a standard cell 1.02 V is balanced by a length of 50 cm. What is the emf of A?

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- May 20, 2021

The emf of a battery A is balanced by a length 75 cm on a potentiometer wire. The emf of a standard cell 1.02 V is balanced by a length of 50 cm. What is the emf of A?
Solution:
Given,
balancing length for battery A,

l_{A}

= 75 cm
balancing length for battery B,

l_{B}

= 50 cm
emf of battery A,

E_{A}

= ?
emf of battery B,

E_{B}

= 1.02 V
Now,

\begin{aligned} \frac{E_{A}}{E_{B}} & = \frac{l_{A}}{l_{B}} \\ E_{A} & = 1.02 \times \frac{75}{50} \\ ∴ E_{A} & = 1.53 V \end{aligned}

Hence the emf of battery A is 1.53 V.

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