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Use the following formula:
W - Q = [m c (T1 - T2)]water + [m c (T1 - T2)]kettle
Where W = work done in joules
Q = heat transfer away from the kettle
m = mass of water (and mass of kettle)
c = specific heat capacity of water (and of the material from which kettle is made)
T1 = initial temperature of water/kettle
T2 = final temperature of water/kettle
It depends on how many liters of water. An average kettle holds up to 1.7 liters and takes 3KW. If it takes 3 minutes( 1/20 of an hour) to boil that's 3/20 of a KWh, = 0.15 KWh.
Doing the thermal energy sum, you have say 1.5 liter = 1.5 kg of water raising from say 10 C to 100 C, that's 90 C raise and 1500 grams of water so that makes 135,000 calories. 1 calorie = 4.2 Joules, so we have 567,000 Joules.
1 watt = 1 Joule/sec , 1 KW = 1000 Joules/sec, so 1 KWh = 1000 x 3600 Joules (3600 secs in 1 hour), 1 KWh = 3,600,000 Joules. So 567,000 Joules = 0.1575 KWh.
So the two sums give similar results. If you do a more exact comparison, you could find the efficiency of the kettle from the difference in the two figures, there is bound to be some loss of electrical power, but it should not be much.
Alternative Answers.
For a more accurate answer, use the following formula -
W - Q = [m c (T1 - T2)]water + [m c (T1 - T2)]kettle
Where
W = work done in joules
Q = heat transfer away from the kettle
m = mass of water (and mass of kettle)
c = specific heat capacity of water (and of the material from which kettle is made)
T1 = initial temperature of water/kettle
T2 = final temperature of water/kettle
Then convert your answer from joules to kilowatt hours.
However, the REALLY simple way is to time how long it takes for your kettle to boil, then multiply its nameplate power rating (in kilowatts) by that time (expressed in hours)!
If you want some boiling water to make tea or coffee, you have to use energy to produce it. Why should you consider it wasted? After all, it is not a new fad to want hot water, in the old days people would keep a kettle on the fire, but we don't usually have fires these days, we use electricity or natural gas.
What is a waste is to fill the kettle if you only want enough water for one or two drinks. Just put in enough for what you intend to use and that is not a waste.
You can work out the energy used by looking up the rating of the kettle in watts, and timing how long it takes to boil, and working it out in KWh.
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 bills are usually quoted in "Kilowatt Hours" (KwHr) instead of Joules
So in one hour a kettle uses 1.5 x 1 = 1.5 Kilowatt Hour
A kilowatt is 1000 watts. It depends on the manufactures wattage rating of the kettle. Most kettles fall within the 1250 watt range. In North America, the electrical code limits a 15 amp circuit to 80% of its rated load capacity. This limits the circuit rating to 15 x 120 = 1800 watts x 80% = 1440 watts. Manufactures stay below this limit otherwise there would be a conflict with the electrical code and a circuit could become overloaded when the kettle is plugged in. So to find the kilowatts of a kettle take the watts that are printed on the label and divide it by 1000 to get its kW value.
In North America an electric kettle is usually rated at 1500 watts. Any wattage above this value would trip the circuit breaker because of an over current. The equation used is A = W/V. 1500 /120 = 12.5 amps. At this wattage it stays within the limits of the electrical code's 80% rule of loading of a #14 conductor. Most homes are wired with a #14 size conductor rated at 15 amps, for their branch circuitry.
An example, a kettle at 2000 watts will draw 2000/120 = 16.6 amps, at 2500 watts the draw will be 2500/120 = 20.8 amps and 3000 watts it will draw 3000/120 = 25 amps.
To change from watts to kilowatts divide the figure by 1000. This will give you the value in kilowatts. It is this kilowatt value that is read by the utility meter on your home.
So to answer the question a kettle will use 1.5 kilowatts of power all the time that it is on. If it was left on for an hour without it being turned off you would be charged for 1.5 kilowatt hours of power use.
To calculate the amperage, you can use the formula: Amperage = Power (watts) / Voltage (volts). In this case, for a 2.2kW kettle at 240 volts, the amperage would be 9.17 amps.
The formula you need to use is I = W/E. Use this, easier for the average person: The conversion of Amps to Watts is governed by the equation Watts = Amps x Volts. For example 1 amp * 110 volts = 110 watts 500w = 250v X A amps Therefore: 500w/250v= 2amps
Kitchen refrigerators use 50-100 watts for about five minutes per hour, so 10 watts or less on average.
To calculate the output amps of a 600kVA generator at 240V, you would use the formula Amps = kVA / Volts. In this case, it would be 600kVA / 240V = 2500 amps.
To find the amperage, you can use the formula: Amps = Watts/Volts. Plugging in the values, you get Amps = 1800 Watts / 110 Volts ≈ 16.36 Amps.
an average typical one would use1800
It takes 13 amps Varies - but around 10 is a good average.
To calculate the amperage, you can use the formula: Amperage = Power (watts) / Voltage (volts). In this case, for a 2.2kW kettle at 240 volts, the amperage would be 9.17 amps.
10 amps
C batteries use 1.5 volts. The number of amps depends on what device it is hooked up to. An average for four C batteries would be about 16 amps.
a regular toaster uses about 12.5 amps
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An average home nowadays has a 200 amp panel. The dryer and stove use 30 and 40 amps and almost everything else is 15 amps.
amps like.. amplifiers? it depends on how many speakers you have. or amps like.. current draw? again. depends on your power needs, your power amps... ect
The formula you need to use is I = W/E. Use this, easier for the average person: The conversion of Amps to Watts is governed by the equation Watts = Amps x Volts. For example 1 amp * 110 volts = 110 watts 500w = 250v X A amps Therefore: 500w/250v= 2amps
yes "How to use a kettle" could be taken as a question, although not a particularly well composed question. A better phrasing would be, how do you use a kettle? Another way of asking this would be, I would like to find out how to use a kettle.
You use Ohm's Law to make your calculation. Volts = Amps x Resistance Amps = Volts / Resistance