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Question
Two cells each having an e.m.f. of 2 V and an internal resistance of \(2,\Omega\) are connected in series as shown in Fig. What is the current flowing through the circuit in each case?
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Solution
Given: EMF of each cell, \(E=2\,V\)
Internal resistance of each cell, \(r=2\,\Omega\)
External resistance, \(R=4\,\Omega\)
When cells are connected in parallel,
Equivalent EMF:
\[ E=2\,V \]
Equivalent internal resistance:
\[ r=\frac{2\times2}{2+2}\]
= 1 Ω
Current flowing:
\[ I=\frac{E}{R+r}\]
\[=\frac{2}{4+1} \]
\[ {=0.4\,A} \]
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