AAI ATC Junior Executive 27 Jul 2022 Shift 2 Paper

Two batteries E1 (emf: 6 V, internal resistance: 0.5 Ω) and E2 (emf: 12 V, internal resistance: 1.0 Ω) are connected in parallel by connecting their positive terminals to point A and negative terminals to point B. A third battery E3 [emf: 6 V, internal resistance: ($\frac{2}{3}$) Ω] is connected in series with this combination by connecting its positive terminal to B. The equivalent emf of this combination is