A battery supplies a current of 2.0 A when a 1.5 Ω resistor is connected across its terminals and 0.8 A when the resistor is increased to 4.0 Ω. What is the EMF and internal resistance of the battery?...

A battery supplies a current of 2.0 A when a 1.5 Ω resistor is connected across its terminals and 0.8 A when the resistor is increased to 4.0 Ω. What is the EMF and internal resistance of the battery?

Four batteries, each of EMF 2.0 V and internal resistance 0.2 Ω are connected in parallel. What is the total EMF and internal resistance of the arrangement?