Question
Question: There is a fixed potential difference between two ends of a potentiometer. Two cells are connected i...
There is a fixed potential difference between two ends of a potentiometer. Two cells are connected in series in such a way that in one arrangement they help each-other whereas in second arrangement they oppose each-other. The balance points for these two arrangements are obtained at 120 cm and 60 cm length respectively. The ratio of emf of two cells is-
A
2 : 1
B
3 : 1
C
1 : 1
D
4 : 1
Answer
3 : 1
Explanation
Solution
ε1+ε2ε1+ε2 = 60120
ε1 + ε2 = 2ε1 – 2ε2
ε1 = 3ε2
∴ ε2ε1 = 13