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Define the emf of a cell in terms of the...

Define the emf of a cell in terms of the work done in moving a charge through the cell. Using Joule.s law obtain the equation, emf=i(R + r). (The symbols have their usual meaning).

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Start with differential equation `E=(dW)/(dt)` and use the relation `i=(dq)/(dt)&V=iR`.
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