There are 27 cells with an internal resistance 0.4 ohms and an external resistance 1.2 ohms. What is the most effective way of grouping them?
- (a)All the cells are in series
- (b) All the cells are in parallel
- (C) 9 parallel branches with 3 cells in each branch
- (d) 3 parallel branches with 9 cells in each branch
Solution:
Let there be n cells in series having m parallel branches
mn = 27 … (1)
mR = nr … (2)
1.2 m = n (0.4)
3m = n … (3)
From equations (1) and (3) , we get m = 3 and n = 9.
i.e. 3 parallel branches with 9 cells in each branch