In a potentiometer arrangement, a cell of emf 1.25 V gives a balance point at 35.0 cm length of the wire. If the cell is replaced by another cell and the balance point shifts to 63.0 cm, what is the emf of the second cell?
Correct option is B) Given : E1=1.25V,l1=35cm,l2=63cm Step 1: The potential gradient of wire, K=lE will remain constant, Therefore EMF of external cell is proportional to the balance length ∴E2E1=l2l1 ....(1) Step 2: Substituting the values in equation (1) So, E21.25=6335 or E2=2.25V
