In a potentiometer arrangement, a cell of emf `2.25V` gives a balance point at `30.0` cm length of the wire. If the cell is replaced by another cell and the balance point shifts to `60.0` cm, then what is the emf of the second cell?

Options

A. 4.5 V
B. 6.5 V
C. 5.6 V
D. 7.0 V

Answer

A

Explanation

Given, `E_(1)=2.25 V, l_(1)=30.0 cm` and `l_(2)=60.0`
We know that `(E_(1))/(E_(1))=(l_(1))/(l_(2))`
`rArr " " (2.25)/(E_(2))=(30.0)/(60.0)`
`E_(2)=(2.25xx60)/(30)=4.5 V`