Problem 3.180

Find the emf and the internal resistance of a source which is equivalent to two batteries connected in paralle] whose emf's are equal to $\mathscr{E}_ {1}$ and $\mathscr{E}_ {2}$ and internal resistances to $R_{1}$ and $R_{2}$ .

\mathscr{E}=\left(\mathscr{E}_{1} R_{2}+\mathscr{E}_{2} R_{1}\right) /\left(R_{1}+R_{2}\right), \quad R_{i}=R_{1} R_{2} /\left(R_{1}+R_{2}\right)

Electric Current