From the given circuit,
Find
(i) Equivalent emf of the combination
(ii) Equivalent internal resistance
(iii) Total current
(iv) Potential difference across external resistance
(v) Potential difference across each cell

Explanation

(i) Equivalent emf of the combination
`xi_(eq)=n xi=4xx9=36V`
(ii) Equivalent internal resistance `r_(eq)=n r`
`=4xx.01=0.4Omega`
(iii) Total current `I=(n xi)/(R+n r)=(4xx9)/(10+(4xx0.1))=(4xx9)/(10+0.4)=(36)/(10.4)`
`I=3.46A`
(iv) Potential difference across external resistance `V=IR = 3.46xx10=34.6V`. The remaining 1.4V is dropped across the internal resistance of cells.
(v) Potential difference across each cell
`(V)/(n)=(34.6)/(4)=8.65V`