Two cells `A` and `B` with same `e.m.f` of 2 V each and with internal resistances `r_(A)=3.5Omega` and `r_(B)=0.5Omega` are connected in series with an external resistance `R=3Omega` Find the terminal voltages across the two cells.

Explanation

Current through the circuit
`i=(epsi)/((R+r))=(2+2)/((3+3.5+0.5))=(4)/(7)`
(i) `R=3Omega,r_(A)=3.5Omega,E=2V`
Terminal voltages A, `V_(A)=E-ir`
`=2-(4)/(7)xx3.5=0` volt
(ii) `r_(B)=0.5Omega,R=3Omega,E=2V`
Terminal voltage at B, `V_(B)=E-ir`
`=2-(4)/(7)xx0.5=1.714` volts