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 58 A-h, 10 V car battery
(b) a 1.3 A-h, 1.7 V flashlight battery

Answer 1

Step-by-step explanation:

Electrical energy = V x Q where V is potential difference or emf in volt and Q is charge in coulomb , energy is in joule .

a )

V = 10 volt

Q = 58 x 60 x 60 coulomb = 208800 coulomb or A-s

Electrical energy = 10 x 208800 = 2088 x 10³ J = 2088 kJ .

b )

V = 1.7 volt

Q = 1.3 x 60 x 60 coulomb = 4680 coulomb or A-s

Electrical energy = 1.7 x 4680= 7956 J .