Question

A typical lead acid storage battery like the one found in your car is 12 V and is rated at 70 amp-hr (70 amp of current drawn for 1 hour). Volts x Amps gives you Watts.

So the energy stored in the fully charged battery is 840 Watt-hours (Wh). Remember that a kWh = 3600 kJ.

If a Snicker's bar contains 250 Cal and 1 Cal = 4.184 kJ, how many Snicker's bars worth of energy is stored in your battery?

a. Fewer than 5

b. 5-20

c. 20-50

d. 50-100

e. More than 100

Answer 1

Almost 3 snicker's bar will contain the worth of energy stored in the battery which makes option A correct (Fewer than 5)

Step-by-step explanation:

Step 1

The energy stored in a charged battery is 840 Watt- hours

Recall from the question that 1 KWh = 3600 KJ

So how many Kilo-joules will be in 840 Watt- hours?

I will convert 840 Watt- hours to KWh = 840 / 1000

= 0.840 KWh

Since I KWh gives 3600 KJ

then, 0.840 KWh will give x

x = 3024 KJ

3024 KJ of energy is stored in the battery

Step 2

A snicker bar contains 250 cal and 1 cal = 4.184 KJ

Convert 250 cal to KJ?

250 cal = 1046 KJ

Each snicker bar contains 1046 KJ

To calculate how many snicker's bar worth energy stored in the battery will be (y) ?

y = 3024 / 1046

y = 2.9 snicker's bar approximately 3

The correct option is Fewer than 5