Electric current that repeatedly reverses direction, twice each cycle. Usually at 60 cycles per second (or Hertz) in North America…50 Hz elsewhere

The rate at which electrical energy is converted into another form, such as light, heat or mechanical energy

AC/DC

A battery produces direct current b/c the terminals always have the same sign

What is the purpose of the bolts on the monster’s neck?

http://www.ehow.com/info_8080445_happens-jumper-cables-reversed-battery.html

Electrons always move through the circuit in the same direction…from the repelling negative terminal to the attracting positive terminal

Remember…in the US we use primarily 120 v, but 240 in dryers and stoves

We also use 60 Hz or 60 cyles/s

The popularity of A/C over D/C is 1) transmitted over greater distances (1

mi DC between power plants, hundreds of mi A/C)

2) lower heat loss in wires

https://www.youtube.com/watch?v=kn-nhXMhXQ4

Electric Power = current x voltage

P = I x V

watts = ampere x volt

1 kilowatt =

1 kilowatt-hour=

1000 watts

1 kilowatt consumed in 1 hour

A 4-watt night light is plugged into a 120 v circuit and operates continuously for 30 days.

a)How much current does it draw?b)How much resistance is in the filament?c)What is the cost of its operation for the month at the utility rate of 10 cents per kilowatt-hour?

A plasma tv draws 2 A when operated on 120 V.

How much power does the tv use? If the tv is operated for an average of 7

hr/day, what energy in kWh does it consume per month (30 days)?

At 11¢ per kWh, what is the cost of operating the tv per month?

A 6.0 V battery delivers a 0.50 A current to an electrical motor. What power is consumed by the motor?

P = IV

P = (0.50 A)(6.0 V)P = 3.0 W