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That depends both on the light bulb's power rating, and how long you want to light it! Use the formula:
energy = power x time
If the power is in watts and the time in seconds, then the energy will be in joules (= watt-seconds).
Alternately, if the power is given in watts, you can divide by 1000 to convert to kilowatts. Then, if you multiply by hours, you get kilowatt-hours. Note that the unit used by utility companies tp charge you is kilowatt-hours.
Wiki User
∙ 10y ago
Wiki User
∙ 8y agoDoesn't work like that. Watts and kilowatts are the RATE at which energy is consumed, NOT the amount. Amount would be measured in watt hours, or kilowatt hours, or amp hours(for batteries) or even Joules, as examples.
To know how long, you need to know both rate and the amount available.
100 W = 0.1 kW
So if you have 1 kWh, it would keep a 100W/0.1 kW lamp burning for 10 hours.
Wiki User
∙ 13y agoThis information is written on the glass of the bulb. Incandescent bulbs are usually sold as 40, 60, 100, and 150 watts. Energy saving bulbs use much less, for instance a 20 watt energy saving bulb will produce about as much light as a 100 watt incandescent bulb.
The watt reading on the bulb is the number of watts used per hour (ie kwh).
Additional AnswerThe power of a lightbulb is printed on its glass envelope, and expressed in watts (W). Power describes the rate at which it uses energy. Energy (for electricity bills) is expressed in kilowatt hours(kW.h).
To determine how many kilowatt hours are used by the lamp, you multiply its power rating (expressed in kilowatts) by the time (expressed in hours) it is in use. The answer, incidentally, will be approximate, because the power rating of the lamp only applies at its rated voltage, and the actual voltage may be different from this rated voltage.
Incidentally, it is incorrect to say that the power rating (watts) is 'the number of (kilo)watts used per hour' because that would need to be expressed 'kilowatts per hour', not 'kilowatt hours', and is completely meaningless because power is already a rate.
Wiki User
∙ 11y agoA lamp doesn't 'have' any energy. But it draws energy from the supply -how much depends upon (a) the rate at which it draws that energy (i.e. the power of the lamp), and (b) how long it operates. The product of its power and the time it operates will tell you how much energy it has used.
Wiki User
∙ 16y agoIt depends on the Wattage of the light bulb. One kWh will power a 100-Watt light bulb for ten hours.
Wiki User
∙ 10y agoLight bulb power is measured in watts, and there are 1000 watts in a kilowatt.
Wiki User
∙ 8y ago1 kilowatt = 1000 Watt
So 100 / 1000 = 0.1
100 W = 0.1 kW. One bulb is 0.1 kW
1 / 0.1 = 10
10 bulbs would be 1 kW
Wiki User
∙ 14y agoA single bulb can be lit with on kilowatt until the bulb burns out or until the power goes off.
Wiki User
∙ 8y agoI kW = 1000 W
100 / 1000 = 0.1
So a 100 W bulb uses 0.1 kW
Wiki User
∙ 10y agoThe amount of power needed to light up a bulb is measured in watts and is marked on the bulb, along with the correct operating voltage. For example 240 v 20 watts.
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Are halogen bulbs more energy efficient than traditional incandescent bulbs?
Well, if they're both 40 watt bulbs they use the same amount of electricity. But incandescent bulbs produce a lot of heat as well as light. Fluorescent bulbs don't produce (much) heat, so they can use their power to produce light. So you can use fluorescent bulbs of lower wattage to produce the same amount of light.So for the same amount of light, fluorescent bulbs use less electricity than incandescent bulbs.
What is the power output of 100 kw power plant?
Your question shows the importance of using the correct symbols, because your symbols are incorrect and, therefore, your question is confusing.So, are you asking how many milliwatts (mW) there are in a kilowatt (kW), or are you asking how many megawatts (MW) there are in a kilowatt(kW)?Notice that the symbol for a watt is an upper-case W. The symbol for a milli is a lower-case m, and the symbol for a mega is an upper-case M.If the former, then there are one-thousand milliwatts in a watt, and there are one-thousand watts in a kilowatt, so there must be one-million milliwatts in a kilowatt.If the latter, then there are one-thousand kilowatts in a megawatt, so a megawatt must be one-thousandth of a megawatt in a kilowatt.
Calculate what a megawatt hour is?
Mega means million and a watt is a unit of power. A megawatt hour is the amount of power used if 1,000,000 watts are used for 1 hour, or 1 watt is used for 1,000,000 hours. If 100 light bulbs each using 1,000 watts of power are turned on for 10 hours, they will use 100 x 1,000 x 10 watt hours = 1,000,000 watt hours = 1 megawatt hour. Most electric companies charge for the number of kilowatt hours used. A megawatt hour is 1,000 kilowatt hours.
There is a 100 watt light left on for 30 days and uses 72 kilowatt-hours suppose thecost of this electricity is 5.76 how much electricity does a 100 watt light bulb use in one week what's the cost?
Check with your electric company. If you switch to 100 W fluorescent bulbs they are only about 14 watts usage. Those are the new energy efficient bulbs. You still get 100 W, but less wattage used. Therefore you bill should be reduced by some. You won't see it right away, it's over the long haul. I have switched most of my lighting (except one lamp and my kitchen) to those bulbs. They last a long long time. I will be switching my kitchen to a new fixture so I will use the 100W energy efficient bulb and get just as much light as 100 incandescent bulb. I'll put 4 in and get 400 W for 56 watts charged. < > < > 5.76/30 days = .192 cents per 24 hour period. .192 x 7 days = 1.344 dollars a week
The problems of electricity two light bulbs of 100 watt and one 60 watt both operation in a 220V circuit. Which bulb has the higher resistance and which bulb carries the greater current?
A 100 watt 220 volt light bulb (or anything consuming 100 watts on 220 volts) draws 100/220, or .45 Amps. It will also have about 220²/100, or 484 ohms resistance. A 60 watt 220 volt light bulb (or anything consuming 60 watts on 220 volts) draws 60/220, or .27 Amps. It will also have about 220²/60, or 807 ohms resistance.
How much electricity load you can drive on 1 kilowatt?
You could power ten 100 watt light bulbs.
What does kilowatt hours mean?
kWh = Power(kW) x Time (hours)AnswerA kilowatt hour (symbol kW.h) is a unit of measurement of electrical energy.
How many 100 watt light bulbs can run with a 1500 watt power inverter?
we can use 12 no's
How many 100 watt bulbs is equal to one 400 watt bulb?
ummm...4(?) is this a trick question?
A 100 watt light bulb left on for 24hrs how many kilowatts does it draw in a thirty day period?
1 kilowatt is equal to 1,000 watts, so a 100 watt bulb uses .1 kilowatt. Technically, your home or business meter base measures kilowatt hours, meaning that it measures both the kilowatts and the amount of time. If you turn on 10 100 watt bulbs for 1 second, that would be a kilowatt, but the amount of power use would be insignificant. So... To calculate the kilowatt hours: .1 kilowatts (from above, knowing the energy use of the bulb) Multiplied by 24 hours in a day Multiplied by 30 days... .1(kilowatts) * 24(hours)* 30(hours in a day) = 72 kilowatt hours
How many 100 watt bulbs can a 110 volt on 100foot line?
17
How many 100 watt light bulbs can 200 kW light?
2000
How many watts does an energy saving light bulb use?
The 100 watt lumen-equivalent bulbs use 20 watts. The 60 watt lumen-equivalent bulbs use 16 watts.
How many watts are in 100 2.5 volt bulbs?
This question does is not answerable. A watt is a volt times an amp. With out knowing how many amps the bulbs use there is no answer.
How many kilowatt hours does a 100 watt light use in 20 hours?
First let us convert the power of the bulb into kilowatts.A kilowatt is 1000 watts. We have one tenth of that. So 100W = 0.1kWTo work out the kilowatt hours we simply multiply the power in kilowatts by the time the bulb is on for (in hours):0.1kW x 10h = 1 kWha 100 watt bulb uses 100 watts of power. In ten hours it uses 100x10 watt-hours, or 1 kilowatt-hour. A kilowatt-hour is also called a unit, and units are what you pay for.
How much does it cost to run a light bulb?
It depends on the bulb, how many watts it is. All bulbs are marked with the correct voltage and the power taken, in watts. You multiply the watts by the number of hours to find the watt-hours of energy used. Then divide by 1000 to find the kilowatt-hours. A kilowatt-hour is also called a unit and you pay about £0.15 for a unit of electricity. Let's say it's a 100 watt bulb running for 24 hours. That uses 2400 watt-hours or 2.4 kilowatt-hours, which costs about 2.4 x £0.15 which is £0.36.
What can you run on a 400 watt inverter?
Four 100 watt light bulbs or anything else that sums to 400 watts.
