Car batteries are often rated in amp-hours. This rating indicates the quantity o
ID: 1440048 • Letter: C
Question
Car batteries are often rated in amp-hours. This rating indicates the quantity of charge that can pass through the battery before the battery's chemical energy must be restored by the car's generator or some other source. The amp-hour unit is convenient for simple calculations. For example, a 60-amp-hour battery can supply a current of 1.0 A for 60 h (or 60 A for 1.0 h) before going dead. Find the energy stored in the following.
(a) a 66 A-h, 11 V car battery__________
(b) a 1.1 A-h, 1.4 V flashlight battery__________
Explanation / Answer
(a) Energy = (volts) • (Amps)•(Hours) = (11) • (66)
Energy = 726 W•hr = 0.726 KW•hr
Energy = (726) • (3600 sec hr) = 2613600 J = 2.61 ×10^6 Joules
(b) Energy = (volts) • (Amps)•(Hours) = (1.4) • (1.1) = 1.54 W•hr
Energy = 1.54 ×3600 = 5544 Joules