Electrical Calculation PDF

[Section 3: Electrical Calculation] [Ohms Law:] - - Term Symbol Unit -------------------------------------------------------------------------------------------------- -------- ------- Curre...

[Section 3: Electrical Calculation] [Ohms Law:] - - Term Symbol Unit -------------------------------------------------------------------------------------------------- -------- ------- Current(the rate at which electric charges pass a specific point) I Amp Voltage( the potential difference between 2 points in a circuit) V Volts Resistance(Electrical friction, the opposition presented to the current by a material or device) R Ohm Ω Power(the rate at which electrical energy is converted into other forms of energy) P Watt How do electrical power companies sell energy to homes and businesses? They calculate it by using electrical energy = power x time, E=PxT. P has to be measured in **KiloWatts,** and time is in **hours.** - - - - [Practice Sheet:] 1. E= PXT, 30w= 0.03 kw, 0.03x3= 0.09KWhr 2. 3. 4. 5. [Practice Questions:Slide 11] 1. **A: what is the power rating for the television** P=VXI,=0.42x120=50.4 W **B: if the TV is operated for 8 hours per day, how much energy in kWh does it use per day?** 50.4/1000=0.0504 KWx8 hours= 0.4032 KWhr **C: At \$0.15 per KWH, what does it cost to run the TV for 30 days** 2. A:300W= 0.3 KWhr 0.3x 24= 7.2 KWhr per day 7.2x8= 57.6 cents/day 7.2x7= 50.4 KWhr per week 50.4x8= 403.2 cents/per week B: for a month? 57.6x30=1728 cents/month C: For a year? 57.6x365= 21024 cents/year \$210.24 per year 3. An average light bulb has a life expectancy of 1,000 hours. How much energy would a typical 60 watt bulb use in a lifetime, assuming it lasts for 1,000 hours? At 3 LE/KWh, how much would it cost over its lifetime? 60 watt= 0.06 KW 0.06x1,000= 60 kWh 3 LEx60Kw= 180 LE/KWhr