Ten cells, each having internal resistance 1 and emf 1.5 V are connected in series. But unknowingly 3 cells are connected wrongly in series. The effective internal resistance and emf of the series combination are respectively:

Step-by-step solution

The total number of cells is n = 10 . Each cell has an emf E = 1.5 V and internal resistance r = 1 . When cells are connected in series, the total internal resistance is the sum of individual resistances, regardless of their polarity. Thus, the effective internal resistance R_ eq = n r = 10 1 = 10 . For the effective emf, if m cells are connected wrongly, they oppose the remaining (n - m) cells. The effective emf is given by E_ eq = (n - m)E - mE = (n - 2m)E . Given n = 10 and m = 3 , the effective emf is E_ eq = (