A 12-volt battery has terminals A and B and an internal resistance, r, and is connected to an external load resistor as shown in the following circuit. The value of the external load resistor, Rload, in the following circuit is 350 ohms.
Emf: 12V
RLead
Given that the current that flows through the load resistor is I = 0.25 A, calculate the value of the internal resistance, r, of the battery. Use 2 significant figures in your answer.