(a) Define Work, Power and Efficiency (6)

(b) A battery is charged with a constant current of 16 amperes for 11 hours after which time it is considered to be fully charged, its voltage per cell being recorded as 2.2V. Find its ampere hour efficiency if it is (10)

(i) Discharged at a rate of 16 amperes for 10 hours, and

(ii) 28 amperes for 4 hours.

In either case discharge was discontinued when the voltage per cell fell to 1.8 V.