80W * 8 hrs
= 80W *(8*60*60)sec
=2304000 J
=2304 kJ
SOME MORE INFO ABOUT HOW TO SOLVE THE PROBLEM:
A watt measures power, which is a rate: how much energy is used in a given amount of time. 1W = 1 J/s. To think about how to calculate the energy used by a lamp burning energy at the rate of 80W, in 8 hours, it might be helpful to think of analogies to more familiar rates
Take pay rate. I take a job at a pay rate of $9 per hour. If I work for 8 hours, I'll have made $9 the first hour, $18 at the end of the second hour, etc. Or $9/h * 8h = $72.
If I walk at a rate of 4 mile per hour, and I walk for 15 minutes, I'll have walked for 4mi/h * 15 min * (1h/60min) = 4 mi/h * 0.25h = 1 mi.
So to find out how much energy is used, multiply the power (energy rate) by the amount of time the lamp is on, by the number of hours in a second (or divide by the number of seconds in an hour).
volts times amps equals watts, a measure of power. Amps times hours equals amp-hours, a measure of electric charge. Electric charge times voltage is energy. So 120 volts at 10 amps for 4 hours would pass 40 amp-hours of charge, the power would be 1200 watts and the energy would be 4800 watt-hours or 4.8 kilowatt-hours. So volts times amp-hours equals energy in watt-hours.
Kilowatt hours.
Electricity consumption is measured in Kilowatt hours, this is one unit of electric consumption and charged according to your supplier. You have to know how many watts your devices consume. This is sometimes written on the ID tag or plate, or you can use a meter in line. Multiply this wattage number by the hours it is switched on and this will tell you how much it has consumed. e.g. A toaster may consume 1000Watts = 1Kw, if you ran it continuously for an hour it would consume 1 unit of electricity. Toasters don't run for more than a few minutes, so would use less than 1 unit per operation. 3 mins = 0.05hrs Therefore = 0.05 of a unit. A 100W light bulb would consume 1 unit in ten hours. 100W = 0.1 KW. = one tenth of a kilowatt, so ten times this would equal 1 Kw/h, Therefore ten hours.
1,760Wh
You don't need to - the "unit" by which electricity is sold is the kWh.kWh = unit1 kWh = 1 uniteach unit is equal to 1000 watt-hours.CommentThe term, 'unit', is short for 'Board of Trade Unit'. The Board of Trade used to regulate the cost of electricity in Britain.
To determine the joules of energy consumed, you would need to know the conversion factor from the units displayed on the electrical meter to joules. This conversion factor varies depending on factors like the voltage and current of the electricity supply. Typically, 1 unit of energy is equivalent to approximately 3600 joules. So if the meter reads 400 units, the energy consumed would be around 1,440,000 joules (400 units * 3600 joules/unit).
To calculate the wasted energy in a TV, you would multiply the power consumption of the TV (in watts) by the time the TV is left on (in hours). This will give you the energy consumed in watt-hours (Wh). To convert watt-hours to joules, multiply by 3600 (since 1 Wh = 3600 joules).
Electric energy usage on your electric bill is measured in kilowatt-hours (kWh). This indicates the amount of electrical energy consumed over a period of time.
Convert the hours to seconds. 1 watt is 1 joule/second, so the energy (in joules) is simply the power (in watts) x the time (in seconds).
The SI unit for all forms of energy is the joule.
Electric companies typically calculate electric energy usage by measuring the amount of electricity consumed in kilowatt-hours (kWh). This is done using electric meters that monitor the flow of electricity into a property over a given period of time. The total energy usage is then calculated based on the amount of power consumed and the duration of usage.
Assuming that you're truly running the bulb with 12 volts . . .(2 amperes) x (12 volts) = 24 watts = 24 joules per second(24 joules/second) x (60 seconds/minute) x (20 minutes) = 28,800 joulesAlso, in electric-bill terms ... 0.008 kilowatt-hour
Energy = power x time. Convert the numbers into compatible units, and multiply. If you multiply watts x seconds, the answer will be in joules. If you multiply kilowatts x hours, the answer will be in kilowatt-hours.
Energy companies use kilowatt-hours (kWh) instead of joules because kWh is a more convenient and practical unit for measuring the amount of energy consumed by households and businesses. Joules are much smaller units, requiring large numbers for typical energy usage, whereas kWh provides a more manageable figure for billing purposes.
No, amps (amperes) do not directly express the difference in energy. Amps measure electrical current, which is the flow of electric charge. Energy is typically measured in units such as joules or kilowatt-hours.
No, power and energy are related but not the same. Power is the rate at which energy is consumed or produced, while energy is the total amount of work that can be done or produced. Power is measured in watts (W), while energy is measured in joules (J) or kilowatt-hours (kWh).
Watt is a unit of power, which measures the rate at which energy is consumed or produced. Energy is the total amount of work done over time. To calculate the energy consumed or produced, you multiply the power (in watts) by the time (in hours) the device is operating. This gives you the total energy in watt-hours.