Two cells of different emfs and internal resistance are connected in parallel with one another. Find the expression for the equivalent internal resistance of the combination?

Asked by Mrinal | 28th Feb, 2013, 10:29: AM

Expert Answer:

Cells In Parallel: In parallel grouping all anodes are connected at one point and all cathodes are connected together at other point. If n identical cells are connected in parallel

(i) Equivalent emf Eeq = E

(ii) Equivalent internal resistance Req = r/n

(iii) Main current i = E/R+r/n

(iv) Potential difference across external resistance = p.d. across each cell = V = iR

(v) Current from each cell i' = i/n

(vi) Power dissipated in the circuit P = (E/R+r/n)2 R

(vii) Condition for max. power is R = r/n and Pmax = n(E2/4r)

(viii) This type of combination is used when nr > > R

Answered by  | 28th Feb, 2013, 05:55: PM

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