PHYS 2002 Lecture : Lecture 7
Document Summary
We can write this different ways using ohm"s law, v=ir: *so we have 3 ways of calculating electrical power depending on what other quantities are known depending on what other quantities are known. Work and energy have the same units (joules). Electrical companies, like entergy, measure your monthly energy use this way, in units of kilowatt hours (kwh). For example, if you used an average power of 1500 w for 31 days (744 hours), your energy consumption would be: kw51( kw5. 1( At a cost of roughly sh. 13/kwh, this would be a monthly bill of . Thermal losses (losing electrical power by converting it to heat) is proportional to i2 for a given voltage and proportional to v. Circuits where a battery is the power source, are direct current (dc) circuits, where th the current flows in only one direction. t fl di ti i l.
