1. ELECTRICITY REVIEW

2. Charges  There are two types of charges- what are they?  Positive and Negative  Where do positive charges come from?  Protons  Where do negative charges come from?  Electrons  If an object gains electrons, what is its charge?  Negative  If an object loses electrons, what is its charge?  Positive

3. Charges  Predict what will happen if the following charges are brought close to each other.  Positive and Negative Attract  Positive and Positive Repel  Negative and Negative Repel  Negative and Positive Attract

4. Circuits  What is voltage?  The energy charges are given by a battery.  What is current?  The flow of electrons through a circuit.  What is resistance?  The prevention of charges to flow.

5. Ohm’s LawV=IR  If a circuit is powered by a 9.0 V battery and there are 36 Ω of resistance, what is the current in the circuit?  9=I x 36I =.25 A  If a second battery is added to the circuit, the voltage goes up to 18.0 V. If the resistance stays the same, what will happen to the current?  18=I x 36I =.50 AIt gets bigger (doubles)  If the resistance is change and the current is now 0.75 A (still 18 V), what is the new resistance in the circuit?  18=.75 x R R=24 Ω

6. Circuit Types  Is this a series or parallel circuit?  Series  What components make up the circuit?  Three light bulbs and one battery  If the first light bulb is unscrewed, what happens to the other light bulbs?  They will still work because the other paths are still complete.  If the battery was replaced with a 3 V battery, what would happen to the bulb brightness?  They would get dimmer because there is less energy in the circuit. 6V6V

7. Circuit Types  Is this a series or parallel circuit?  Series  What components make up the circuit?  Light bulb, resistor, battery  If the light bulb is unscrewed, what happens to the circuit?  It stops working  If another light bulb is added, what would happen to the brightness of the first bulb?  It would get dimmer because there is even more resistance.

8. Drawings  Draw a diagram of the circuit you see.