AB is a potentiometer wire of length
100 cm and its resistance is
10 Ω. It is connected in series with a resistance
R=40 Ω and a battery of emf
2 V and negligible internal resistance. If a source of unknown emf
E is balanced by
40 cm length of the potentiometer wire, then the value of
E is
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/917441/original_Q16.png)