Problem 16. A fully charged 60.0 A h car battery was continuously discharged at
ID: 3280163 • Letter: P
Question
Problem 16. A fully charged 60.0 A h car battery was continuously discharged at a current of 30.0 A to run an electrical device. During the discharge, the battery delivered current at an average voltage of 8.00 V. The discharge process used up 25 % of the battery's capacity. Afterwards, the battery was recharged to its initial state using a battery charger that delivered an average charging current of 5.00 A at 13.0v (a) What is Qnet for the battery for the combined disharge-charging cycle? (b) Is this heat absorbed or evolved by the battery?Explanation / Answer
a] Qnet for discharge-charge cycle = 0 because whatever was discharged, was charged again.
b] heat in discharging process = iVt = 30*8*(0.25*60*3600/30) = 432000 J
heat in charging = 5*13*(0.25*60*3600/5) = 702000 J
heat is evolved by the battery