please solve the question at the bottom.

When switch S in the figure is open, the voltmeter V of the battery reads 3.13 V . When the switch is closed, the voltmeter reading drops to 2.90 V , and the ammeter A reads 1.68 A . Assume that the two meters are ideal, so they do not affect the circuit. (Figure 1) Figure Part A Find the emf &. Express your answer in volts to three significant digits