Physics: pages

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 10 6 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=I 2 R

E n e r g y l o s s i s p r o p o r t i o n a l t o t h e s q u a r e o f t h e c u r r e n t. D e c r e a s i n g c u r r e n t i s m o r e i m p o r t a n t t h a n d e c r e a s i n g r e s i s t a n c e.

Homework: P. 710 #1,2 P.712 #1,2 P. 713 #1-5