Calculate emf and internal resistance of a battery

Part 1

A battery has an emf E and an internal resistance r. When the battery is connected to a 28.0 W resistor, the current through the battery is 0.604 A. When the battery is connected to a 53.1 W resistor, the current is 0.499 A. Calculate the emf of the battery.
(in V)

Part 2

Calculate its internal resistance.
(in ohm)

Solution Summary

In this exercise, students are asked to calculate the emf and the internal resistance of a battery, when the battery is connected to a resistor in series.