Question
Question: Two cells of emf’s approximately 5 V and 10 V are to be accurately compared using a potentiometer of...
Two cells of emf’s approximately 5 V and 10 V are to be accurately compared using a potentiometer of length 400 cm.
The battery that runs the potentiometer should have voltage of 8 V.
The battery of potentiometer can have a voltage of 15 V and R adjusted so that the potential drop across the write slightly exceeds 10 V.
The first portion of 50 cm of wire itself should have a potential drop of 10 V.
Potentiometer is usually used for comparing resistances and not voltages.
The battery of potentiometer can have a voltage of 15 V and R adjusted so that the potential drop across the write slightly exceeds 10 V.
Solution
: The balance pint can be obtained only if the potential difference across the wire is greater than the emf’s to be compared (or measured). Therefore, option (2) is correct.