A 12 V car battery is rated at 100 Ah (Ampere-hours). How many times could a 0.8 kW camping kettle be boiled, if it takes an average of 5 minutes to boil the kettle?

18 times

Explanation:

We are given;

Voltage of the car battery as 12 V Rating of the battery is 100 Ah Power of the kettle is 0.8 kW Time taken to boil the kettle is 5 watts

We are required to calculate the number of times the kettle can be boiled.

Step 1: Energy released by the battery

Energy = Voltage * Current * time

Voltage = 12 V

Current = 100 Amperes

Time - 1 hour or 3600 sec

Therefore;

Energy from the battery = 12 V * 100 A * 3600 sec

= 4,320,000 Joules

Step 2. Energy required to boil one kettle

Energy = Power * time

In this case;

Power is 0.8 kW or 800 watts

Time = 5 mins or 300 seconds

Therefore;

Energy required to boil a kettle

= 800 watts * 300 seconds

= 240,000 Joules

Step 3: Number of times the kettle that can be boiled.

We divide the total amount of energy from the battery by the energy needed to boil one kettle.

Number of times = 4,320,000 Joules : 240,000 Joules

= 18 times

Therefore, the kettle can be boiled 18 times using energy from the battery.