Test Review Chapter 16 and 17

Major Concepts - Circuits -Parallel vs Series -How to determine current, voltage, resistance and the definition of each -What happens to the circuit when bulbs burn out - Vocabulary -Multimeter, insulators, pot dial, ETC. - Magnets -Attraction and Repulsion -Atoms within a magnet - Compass -Geographic North and South, Magnetic North and South -How would the dial change when a magnet is near by

Electromagnets Electromagnets –How do they work? –Right-hand rule Motors and generators Motors and generators –How do they work? –What is the major difference? Renewable and Non-renewable resources Renewable and Non-renewable resources –Types, sources, –What do we use the most for electricity?

Electrical Power Current x Voltage = Power (P=IV) If you use a 1,500-watt heater for 3 hours. How many kilowatt-hours of electricity did you use? **Remember!! Kilowatt is 1000 watts = 1000J/s

Compass If I place a magnet at different points on the compass what will happen? Earth is an example of what type of magnet? From lab page: 65 Question B What is magnetic declination ?

Electromagnets Current has the ability to create the poles of the electromagnet Current has the ability to create the poles of the electromagnet Right-hand rule: If you place your fingers in the path of the current then your thumb will point in the direction N. Right-hand rule: If you place your fingers in the path of the current then your thumb will point in the direction N. There are two ways to increase the current in a simple electromagnet: There are two ways to increase the current in a simple electromagnet: 1.Apply more voltage by adding a second battery. 2.Add more turns of wire around the nail. But there may be something else!

What should be happening Lab time!

Current Series SAME THROUGHOUT *The current takes one path I = 6V/3Ohms I = 2 amps Parallel DIFFERENT THROUGHOUT The current can take different paths to each resistor The current can take different paths to each resistor I = 12V/3Ohms= 4A

Voltage Series Different Throughout - Voltage drops at each resistor (potential energy lost) - Need to know total voltage V1= 2A x 1 Ohms = 2 volts V2 = 2A x 2 Ohms = 4 volts Parallel Same Throughout The amount of potential energy going to each bulb remains the same because of this awesome circuit Voltage = 12 volts at each branch

Resistance Series - Resistance is a total amount - Add up all the resistors to get total resistance R t = R 1 + R 2 R t = 1 Ohm + 2 Ohm = 3 Ohms Parallel Resistance DOES NOT add up! The resistance you calculate for the entire circuit is basically an average Total Votage/Total Current = Total Resistance V/I = Total R 12 V/ 8A = 1.5 Ohms

Motors To cause the rotor to turn in a counter-clockwise direction, the north pole of a magnet should be placed at position: Remember: Motors USE ELECTRICITY Generators MAKE ELECTRICITY Require 3 Things: