Question

The wire of the potentiometer has resistance 4 ohms and length 1 m. It is connected to a cell of e.m.f. 2 volts and internal resistance 1 ohm. If a cell of e.m.f. 1.2 volts is balanced by it, the balancing length will be:
 
A)  90 cm
B)  60 cm
C)  50 cm
D)  75 cm​

Answer 1

Answer:

Potential gradient = 1.6 v/m  

E.M.F. = potential gradient × balancing length 1.2 = 1.6 × l

l=1.2\1.6

=3\4

3\4=0.75m

convert m into cm 0.75x10

0.75m=75 cm

ans=75 cm

Explanation: