How to find the watts of an appliance?
362045
markey watts = volts x amps , only for a Direct Current device. For AC, which we use in our wall outlets, there is another quantity called the power factor which is the cosine of the phase lag between the voltage and the current:\n\nwatts = volts x amps x powerfactor
517654
Need to know the impedance of the solar panel to determine current.
974255
About plus and minus ten percent. That makes it 108 minimum and 132 maximum volts.\n\nMost appliances are designed to expect this range.
100752
There are two relavent formulas,\nOhms Law: V = R*I\nwhere V is the voltage, R is the resistance, and I is the current.  Also,\nPower = V*I\n\nIf we know that power is 150 watts, then,\n150 = V * I,\nbut what is the current (I)?\n\nWe know the resistance is 95 ohms,\nV = 95*I --> I = V / 95\nSo plugging back into the power equation,\nP = V^2 / R \n150 = V^2 / 95 --> V = sqrt(150 * 95)\nso V = 119.4 volts --> 120 volts
162775
One kilowatt used over a one hour period is one kilowatt-hour.  To find out how many kilowatt hours an electrical appliance uses, look on the label (wattage - say 300 watts).  Divide that by 1000 to get kilowatts (0.3 kilowatts).  Now multiply it by the time you are going to use it for (say 20 minutes [6 kilowatt-minutes] - divided by 60 minutes in an hour [0.1 kilowatt-hours]).  The result should be the number of kilowatt-hours used.
960390
Get an electrical heating element, a DC power supply, a thermometer, a voltmeter and an ammeter.\nPass electricity through the heating element, dipped into a measured volume of water (or salt water) in an insulated cup, and measure the current, the voltage and the time taken. This will give you the heat energy supplied. Measure the temperature rise, and work out how much energy would be required to raise 1g of water (or salt water) by 1 degree Celcius. The answer should be close to 4.2!
579021
I think you meant WATTS versus volts. You will need to inspect your power supply for that information.\n You need to check out he following website, for more info on what you will truly need 250W sounds a bit low by today's standards - http://www.jscustompcs.com/power_supply/
652086
1. volts\n2. (b) negatively charged.\n3.  short.  Could also be "conductor," but the lack of control seems to indicate an unwanted short.\n4.  watt-hours.\n5.  \n6.  (a) The formula is P=V*V/R.  Where V is the voltage and R is the resistance.  So P=45*45/15=135 watts.  Actually the object is consumming the power, not producing it.\n    (b)  135*10 = 1350 watt-hours, or 1.35 kw-hr.\n    (c) 0.08*1.35 = $1.08\n7.  (a)  V=IR, so if the voltage is increased while the resistance is kept constant, then the current will also increase. (I=V/R)\n    (b)  If the resistance is increased and the voltage is kept constant, then the current has to decrease. (I=V/R)
474968
The Watt is a unit of Power.\n\n(I'm pretty sure P does not equal vf though)\n\nEDIT - No you're right. I had to work it out for my own peace of mind though!\n\np=e/t\nw(e)=fd\np=fd/t\np=f(d/t)\np=fv
1117397
Look on the AC/DC power adaptor that came with your computer.  It should say how much power it supplies.  It's on the brick that is between the AC outlet and the DC power plug on your computer.  For mine, it says OUTPUT: 19V - 6.3A(6.3A).  Multiply those two numbers together, and that's how many watts your computer requires.  I have a P35, and I require almost 120 watts.
655289
The units of:\n[Power] = Watts\n[Current] = Amps\n[Time] = Seconds\n[Energy] = Joules\n     \n      also\n\n[Energy] = kWh\n\n1kWh = 3.6 X10^6 Joules\n\nPower = Current X Voltage\n\nEnergy = Power X Time \n\nAfter performing the previous calculation, the units of energy must be converted from Joules to kWh, since electric companies charge in dollar per kWh.\n\n\n$ = Energy (measured in kWh) * Cost of energy in Dollars per kWh\n\nUsually, the cost of electric energy is in the neighborhood of $0.05 and $0.10 per kWh.
508033
1.125 KW or 1125 Watt
171175
P=IV\n =12.5*120\n =1500W\n =1.5KW
616652
Most generators are rated in watts. If you have a 50 amp circuit, then 110 volts x 50 amps = 5500 watts. You do not want to run the generator past 80% of its duty cycle, so a 6000 watt gen should be the best.\nHope the formula helps\nYou can also figure out how many watts a microwave will need. I it takes 10 amps at start up then 10 x 110 = 1100 watts.\nThus a 60 watt light bulb would take 60/110= .54 amps
795841
1 calorie = 4.184 Joules\n1 Joule = 1 watt-second, so\n1calorie (C) = 4.184 w-s\n(100 C/hr)(1 hr/3600 s)(4.184 w-s/C) =\n0.11622... watts
1130014
V=IR\n\nWire 1:\n50 = 2 * R1 => R1 is 25 ohms\nCurrent = 2 amps\npower = V*I = 2*50 = 100 watts\n\nWire 2: \n100= 2* R2 => R2 = 50 ohms\nCurrent=2amps\npower = V*I = 100*2 = 200 watts\n\nare you looking for ratios when you say "compare" ?\nif yes: ratio of resistances is  1:2\nratio of currents is 1:1\nand ratio of power is 1:2
846683
You need to know the luminous efficacy to convert lumens into watts: http://en.wikipedia.org/wiki/Luminous_efficacy