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How to convert the formula of electric energy: 1 degree = 1 kwh = 3.6 * 10 ^ 6 joules
w==Pt=1Kw×1h＝1000w×3600s＝3.6×10^6J
KWh and j
What does it ask to answer kW. Or J?
For example, how much electricity is consumed by XXX
According to the meaning of the question, the unit of energy is kW. H or J. the international unit of energy is J. kW. H is mostly used for electric energy calculation, because the power of electrical appliances is expressed by kW or W. the work done is obtained by multiplying power by time. The relationship between kW. H and J can be obtained by converting the unit of kW. H into international unit, that is, 1kW. H = 1000W × 3600s = 3600000j
At present, energy-saving lamps are gradually replacing incandescent lamps. The brightness of a 220 V 12W energy-saving lamp is the same as that of 220 V, 60 W incandescent lamps
(1) What is the work done by the current of "220 V 60 W" incandescent lamp working normally for half an hour?
(2) If the working time of a certain lamp is 2000 hours per year, how many kilowatt hours of electricity can be saved by replacing the 220 V 60 W incandescent lamp with a 220 V 12 W energy-saving lamp?
(3) Given that the luminous rate of incandescent lamp is only 8%, what is the luminous rate of energy-saving lamp?
1) Half hour = 1800sp = w / T, w = P · t = 60W × 1800s = 108000j (2) P energy-saving lamp: 12W = 0.012kwp incandescent lamp: 60W = 0.06kwp = w / T, w energy-saving lamp = P energy-saving lamp · t = 0.012kw × 2000h = 24kw · HW incandescent lamp = P incandescent lamp · t = 0.06kw × 2000h = 120kw · h1kw · H = 1 degree w White
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