A 100W light bulb is left on for 10hrs. Over this period of time how much energy is used by the bulb?
am i doing this right?
my guess is to convert 100W to kW
and convert 10 hrs to seconds and multiply the 2 together?
which gives 3600J or should i just leave it in watts?
Energy is in joules. Power is in watts.
Sometimes electrical energy is spoken of as watt-hours, or watt-seconds, or kw-hrs. But in the end, joules is energy.
Multiply watts x time to get energy.
To calculate the energy used by the light bulb over a period of time, you need to determine the total amount of electrical energy consumed. Here's how you can approach this:
1. Convert the power rating of the light bulb from watts (W) to kilowatts (kW). To do this, divide 100 by 1000:
100 W ÷ 1000 = 0.1 kW
2. Multiply the power rating in kilowatts by the time duration in hours (10 hours) to calculate the energy used:
0.1 kW × 10 hrs = 1 kilowatt-hour (kWh)
The answer is 1 kilowatt-hour (kWh), which represents the total electrical energy consumed by the bulb over 10 hours.
Although 1 kilowatt-hour (kWh) can be converted to other energy units, such as joules (J), it is typically more convenient to keep it in kilowatt-hour since it is a commonly used unit for measuring electricity consumption in households.
So, you did it right!