power, work and energy in electrical circuits. potential difference 1 v = 1 j 1 c
TRANSCRIPT
Power, Work and Energy in Electrical
Circuits
Potential Difference
1 V = 1 J1 C
Power Units
1 V =1 J1 C 1 A =
1 C1 s
(1A)1V =(1J)1C(1C)1 s =1W
Power
P=VI
Work
W=P t
W=V I t
Work-Energy Theorem
W=TE
Heating
In the real world, much of the electrical energy of a
circuit is turned into thermal energy.
Kilowatt-Hours
Most electric bills are calculated using the kilowatt-hour as the unit. A kilowatt-hour is an amount of energy.
3600 10001 1 1 3,600,000
1 1s W
kWhr kW hour Jhour kW
Cost - 20¢ kWhr
What is the cost of running a 60 W incandescent bulb for 1000 hours?
What is the cost of running a 13 W CF bulb for 1000 hours?
60 1000 60,000 60W Pt Whr kWhr
60 0.20 12.00Cost
13 1000 13,000 13W Pt Whr kWhr 13 0.20 2.60Cost