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Question
A cell of e.m.f ε and internal resistance r is used to send current to an external resistance R. Write expressions for
- the total resistance of circuit.
- the current drawn from the cell.
- the p.d. across the cell.
- voltage drop inside the cell.
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Solution
- Total resistance = R + r
- Current I = `"potential"/"Resistance"`
= `ε/("R" + r)` - p.d. across the cell : `(ε/("R"+r)) xx "R"`
- voltage drop inside the cell = I × Resistance
=`ε/(("R"+r))xxr`
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