A chocolate chip cookie contains about 200 kcal. How many kilowatt-hours of energy per day does it contain. How long could you light a 100-W light bulb with the energy from the cookie?
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To answer these questions, let's start by understanding the units of energy involved.
1. Kilocalorie (kcal): A unit commonly used to measure the energy content of food.
2. Kilowatt-hour (kWh): A unit used to measure electrical energy consumption.
3. Watt (W): A unit of power used to measure the rate of energy transfer.
Now, let's calculate the answers:
1. To convert the energy content of the chocolate chip cookie from kcal to kilowatt-hours (kWh), we need to account for the conversion factor. 1 kilocalorie (kcal) is equal to 0.001163 kilowatt-hours (kWh).
Therefore, to convert 200 kcal to kWh:
200 kcal * 0.001163 kWh/kcal ≈ 0.233 kWh
So, a chocolate chip cookie contains approximately 0.233 kilowatt-hours of energy.
2. To determine how long you can power a 100-Watt (W) light bulb with the energy from the cookie, we need to divide the total energy of the cookie (in kilowatt-hours) by the rate of energy consumption of the light bulb (in kilowatts).
Energy consumed per day = 0.233 kWh
Power of light bulb = 100 W
To convert the power of the light bulb from Watts to kilowatts, we divide by 1000:
Power of light bulb = 100 W / 1000 = 0.1 kW
To calculate the time the light bulb can be lit, we divide the energy consumption by the power:
Time = Energy / Power
Time = 0.233 kWh / 0.1 kW ≈ 2.33 hours
Therefore, with the energy from the chocolate chip cookie, you could light a 100-Watt light bulb for approximately 2.33 hours.