How many joules of energy are required to run a 100 W light bulb for one day? Burning coal yields about 30x10 to the 8J of energy per kilogram of coal burned. Assuming that the coal power plant is 30% efficient, how much coal has to be burned to light the bulb for one day?
0.96 kg
To determine the energy required to run a 100 W light bulb for one day, we need to calculate the total energy consumption.
First, we need to convert the power (100 W) to energy by multiplying it by the time (one day) in seconds:
Energy (Joules) = Power (Watts) x Time (seconds)
Energy = 100 W x (24 hours x 60 minutes x 60 seconds)
Energy = 100 W x 86,400 seconds
Energy = 8,640,000 Joules
Therefore, 8,640,000 Joules of energy are required to run a 100 W light bulb for one day.
Next, let's calculate the amount of coal that needs to be burned. Assuming that the coal power plant is 30% efficient and burning coal yields 30 x 10^8 J per kilogram, we can determine the amount of coal needed.
Energy generated from burning one kilogram of coal = Efficiency x Energy content of coal
Energy generated = 0.30 x (30 x 10^8 J/kg)
Energy generated = 9 x 10^7 J/kg
Now, divide the total energy required (8,640,000 Joules) by the energy generated per kilogram of coal (9 x 10^7 J/kg) to find the amount of coal required:
Amount of coal (kg) = Total energy required / Energy generated per kilogram of coal
Amount of coal = 8,640,000 J / (9 x 10^7 J/kg)
Amount of coal = 0.096 kg
Therefore, approximately 0.096 kilograms (or 96 grams) of coal would need to be burned to light the 100 W light bulb for one day.
To determine how many joules of energy are required to run a 100 W light bulb for one day, we need to calculate the total energy consumed by the light bulb during that time.
First, let's convert the power of the light bulb from watts (W) to joules per second (J/s). Since 1 watt is equal to 1 joule per second, a 100 W light bulb will consume 100 joules of energy per second.
Next, we need to determine how many seconds are in one day. There are 24 hours in a day, and each hour has 60 minutes. Considering that each minute has 60 seconds, we can calculate:
1 day = 24 hours * 60 minutes * 60 seconds = 86,400 seconds
Therefore, the light bulb will be running for 86,400 seconds in one day.
Now, we can calculate the total energy consumption by multiplying the power (in joules per second) by the time (in seconds):
Energy consumed = Power * Time
= 100 J/s * 86,400 s
= 8,640,000 joules
So, approximately 8,640,000 joules of energy are required to run a 100 W light bulb for one day.
Now, let's determine how much coal needs to be burned to produce this amount of energy, considering the efficiency of the coal power plant.
We know that burning coal yields about 30x10^8 J of energy per kilogram of coal burned. However, the coal power plant is 30% efficient, meaning that only 30% of the energy contained in the coal is converted to usable energy.
To calculate the amount of coal needed, we can use the equation:
Amount of coal (in kilograms) = Energy required / (Efficiency * Energy content of coal)
Substituting the values, we get:
Amount of coal = 8,640,000 J / (0.30 * (30x10^8 J/kg))
= 2.88 kg
Therefore, approximately 2.88 kilograms of coal need to be burned to light the 100 W light bulb for one day.