find the emf `(epsi_(0))` and internal resistance `(r_(0))` if a battery which is equivalent to a parallel combination of two batteries of emfs `epsi_(1) and epsi_(2)` and internal resistances `r_(1) and r_(2)` respectively, with polarities as shown in figure.

Answer

`epsi_(0)=(epsi_(1)r_(2)-epsi_(2)r_(1))/(r_(1)+r_(2)),r_(0)=(r_(1)r_(2))/(r_(1)+r_(2))`