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Two cells of emfs ει & ε2 and internal resistances r1 & r2 respectively are connected inparallel. Obtain expressions for the equivalent resistance and emf of the combination |
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Answer» We have two cells E1 and E2 with internal resistance r1 and r2 connected in parallel with a resistor R.Let, I1 and I2 be the current through E1 and E2 respectively.By applying KCL(Kirchhoff's Current Law),I = I1 + I2Let there resultant EMF is Eeff and resultant resistance be Req.By KVL(Kirchhoff's Voltage Law)Potential across R = Eeff - I*ReqPotential across upper branch = E1 - I*r1Potential across Lower Branch = E2 - I*r2After solving we will getEeff = (E1/r1 + E2/r2)*ReqandReq = r1*r2/(r1 +r2) Eequa=(E1R2+E2R2)/(R1+R2) |
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