Question

24 cells, each having the same e.m.f. and 2 ohm internal resistance, are used to draw maximum current through an external resistance of 3 ohm. The cells should be connected :
(A) in series
(B) in parallel
(C) in 4 rows, each row having 6 cells
(D) in 6 rows, each row having 4 cells​

Answer 1

Given:

24 cells, each having the same e.m.f. and 2 ohm internal resistance, are used to draw maximum current through an external resistance of 3 ohm.  

To find:

The cells should be connected :

Solution:

The net EMF in each row = nε = 6  

The net resistance in each row = 2 × 6 = 12 Ω

In parallel the net EMF will be 6  

Net resistance  n/r ​= 4/12 = 3 Ω

Net current = 6/(3+3) = 6/6 = 1 A

Option (C) in 4 rows, each row having 6 cells is correct.