An external resistor R is connected between the terminals of a battery. The value of R varies. For each R value, the current I in the circuit and the terminal voltage V_abof the battery are measured. The results are plotted in Fig. P25.74, a graph of V_abversus I that shows the best straight-line fit to the data.

(a) Use the graph in Fig. P25.74 to calculate the battery€™s emf and internal resistance.

(b) For what value of R is V_ab equal to 80.0% of the battery emf?

Figure P25.74

Transcribed Image Text:

Vab (V) 32.0 28.0 24.0 I (A) 20.0 2.00 3.00 4.00 5.00 6.00 7.00 8.00