# Why do you use kilowatt hours instead of joules?

A Joule is too small a unit. You would not use a nanometre to measure everyday things!

### How are mw and kwh related you understand how mw and kw or mwh and kwh are related but cannot find a relationship to answer your question?

Joule is a unit of energy; Joule is the same as watt-second. A watt is a unit of power, meaning, joules/second (joules per second). It is used to measure how fast energy is produced, used up, or transferred. kilowatt (1000 watts) and megawatt (1,000,000 watts) are simply multiples of the watt. Electricity bills use the unit kilowatt-hours - it refers to the energy you use if you use a power of one kilowatt, during an…

### How many watts does one bulb use?

Look on the end of the bulb for the wattage rating. Multiply this by the time the bulb is on and you will get watt/hours. Comment The above answer should read watt hours, not watt/hours. It's also worth pointing out to the questioner that a lamp does not 'use' watts. A watt is the unit of power, and power is the rate at which the lamp uses energy. In the SI system, the unit of…

### How much power does a 60 watt fluorescent bulb use?

First of all, lamps (or any other electrical appliance, come to that) don't 'use' power. 'Power' simply tells you the rate at which your lamp consumes energy. A 60- W lamp is using energy at the rate of 60 joules per second -i.e. for every second the lamp is on, it is consuming 60 joules of energy. This is because one watt is equivalent to one joule per second. To complicate matters, however, your electricity…

### The kilowatt hour is unit of what quantity or quantities?

The kilowatt-hour is a unit of energy. The basic metric unit of energy is the Joule. If you use energy at the rate of 1 Joule per second, you are using '1 watt' of power. If you use 1,000 Joules per second, you're using '1 kilowatt' of power. If you keep it up for an hour (3,600 seconds), you've used a total of 3,600,000 Joules of energy. The other ways to express that amount of…

### How much energy does it take to power a light bulb?

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…

### How many watts does a kettle use in an hour?

Watts is the wrong unit. It is a measure of energy usage, not total power consumed. This question is like saying "How many Km per Hour do you go in an hour". A "Joule" is the scientific unit of energy. 1 Watt = 1 Joule per second. A typical kettle uses between 1 and 2 Kw (Kilowatts). So in one hour it would use 1.5 x 1 x 60 x 60 = 5400 Joules. Electricity…

### 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…

### How many kilowatts do you use per day?

You don't "use" kilowatts; you use kilowatt hours. The kilowatt is an unit of power. Power is the rate at which you use energy which, for electrical installations, is measured in kilowatt hours. Put another way, power is an instantaneous value, whereas energy is an accumulated value. In simple terms, you can compare 'power' with 'miles per hour', and 'energy' with 'miles travelled'.

### How can you calculate the electricity bill for 100 watts by 12 hours?

To calculate an answer, first multiply the watts used by the hours of use. This will give you watt hours. Now divide your answer by 1000 and this will give you kWh of use. Take the kWh of use and multiply it by the cost per kilowatt that your utility company charges you per kilowatt hour. This information can be found on your electric bill or you can give them a call and ask how…

### How many kilowatt-hours does a 100 watt light bulb use in 10 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 = 0.1kW To 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 kWh a 100 watt bulb uses 100 watts of power. In ten hours it uses 100x10 watt-hours, or 1 kilowatt-hour. A…

### What is the meaning of rating of electric bulb as 100 watt?

A '100-W' lamp consumes energy at the rate of 100 joules per second. One unit of electrical energy is a kilowatt hour (1kWh). If you leave the bulb on for ten hours, it will use 1 unit of energy. A 60 watt bulb would take 16 hours 40 minutes to use the same single unit of energy. Answer Power may be defined as 'the rate at which energy is consumed'. It is measured in watts…

### Are kilo watt hours bad for energy?

No, kilowatt-hours are an exact measure of a quantity of energy. Energy is something that can be measured exactly and if you have an electricity supply at your house there is a meter that measures the kilowatt-hours you use. If you have a 40-watt light, it uses 40 watt-hours if it is on for an hour. If it is left on for 24 hours it uses 40 x 24 watt-hours, which is 0.96 kilowatt-hours, that…

### What is the unit of measure for electricity consumption?

Electricity consumption or, more accurately, energy consumption is measured in units called joules (J), although electricity supply companies use a bigger, non-SI, unit called the kilowatt hour. A kilowatt hour is defined as 'the energy consumer, over a period of one hour, at the rate of one kilowatt'.

### How much energy does a 150 watt light bulb use each minute?

The definition of a Watt is 1 Joule/second. Therefore: 150W * 60 Sec = 9000 Joules / minute. In units more applicable home energy use, 9000 Joules/minute equals .0025 Kilowatt Hours (KWh)/minute. On a cost basis, if for example, electricity from a power company costs $.20 per KWh, the 150W light bulb costs 3 cents per hour to use.

### How much does electricity cost retail per kilowatt?

I pay .07 cents a kilowatt. Answer A kilowatt measures power, which is the rate at which you use energy. You do not pay for power but, rather, for energy. For the purpose of billing consumers, energy is measured in kilowatt hours (kW.h). So, the above answer should read 0.07 cents per kilowatt hour.

### What is the common unit used for electrical energy consumption?

== Current and Power and Energy == The unit used to measure the flow of electricity, or current, is the ampere (A). The unit to measure power is the watt (W). Energy is measured in Joules (J). Amperes are really a measure of a rate of electron flow (electrons per second), or equivalently, how much charge is passed per second (Coulombs per second). 1 A = 1 Coulomb per second, and 1 electron has a…

### What total wattage does an electric light bulb use in a day?

In the U.S. all home light bulbs use 120 volts constantly. You may mean electrical power (watts) instead of voltage. If so, different light bulbs use different amounts of power. Typical general service incandescent light bulbs (ordinary old fashioned light bulbs) use about 1200 watts-hours (1.2 kilowatt hours) if burned all day and night. Twice that much for 100 watt bulbs. Compact fluorescent bulbs that produce a similar amount of light output use about 300…

### What is the expression for energy?

Energy = force x distance Energy= power x timeEnergy can be measured in several different units. The SI unit is the Joule, and 1 joule/sec is 1 watt. Thermal energy can be measured in calories or BTU. There is an equivalence, 1 calorie = 4.2 Joules. In the ft-lb system, energy can be measured in units of ft.lbforce (ftlbf), and 1 ftlbf = 1.356 Joules. In electrical systems we use kilowatt-hours.