• Physics: pages 708-713

Direct vs. Alternating Current

In direct current the current continually moves in only one direction. Batteries use this type of current to generate electric power.

In alternating current, the charge carriers continually change direction of movement (back and forth) in opposite directions. Most devices run off of this type to minimize loss of power, since the charge carriers do not actually have any displacement.

That’s all the power she’s got Captain!

What? Watt?

Electric companies

measure energy consumed in

kilowatt-hours

You are charged money per

kilowatt-hour used at your home.

3.6 x 106 J

Electric energy is transferred at high

potential differences to

minimize energy loss

The power dissipated by a resistor can be found with this

equation

P=I2R

Energy loss is proportional

to the square of the current.

Decreasing current is more

important than decreasing

resistance.

Homework: P. 710 #1,2

P.712 #1,2

P. 713 #1-5