1. Chapter 13 Electricity!

2. Quick review: Conductors Insulators Like charges ___________ and unlike charges _____________. Repel Attract

3. An objects electric charge depends on the imbalance of it protons and electrons. Objects can be charged by the transfer of electrons. Charging by Friction, Conduction and ________________.

5. Electric Force = the force of attraction or repulsion between object due to charge. Electric Force depends on charge and _______________.

6. Voltage and Current! Volt is the SI unit for potential difference. (voltage) (V) A cell is a source of electrical current because of the potential difference, or voltage, between the terminals. A voltage sets a charge in motion. ◦Example: Electrons move from the negative terminal of a battery to the positive terminal when a flash is turned on.

8. Current is the rate that electric charges move through a conductor. ◦Measured in Amperes (A) ◦SI unit I

9. *Conductors have low resistance* Resistance is the ratio of voltage across a conductor to the current it carries. Resistance is caused by internal friction and slows the movement of charges. Resistance = Voltage/Current

10. Practice problems The heating element in an electric kettle has a resistance of 30 Ω. What is the current in the heating element when it is connected to a 230 V supply?

11. A circuit contains a 6 volt battery and a bulb with a resistance of 3 ohms. Calculate the current. What is the voltage of a circuit with 15 amps of current and toaster with 8 ohms of resistance?

12. A circuit contains two 1.5 volt batteries and a bulb with a resistance of 3 ohms. Calculate the current. You have a large flashlight that takes 6 D- cell batteries. If the current in the flashlight is 2 amps, what is the resistance of the light bulb? (Hint: A D-cell battery has 1.5 volts.)__________________

13. Circuits!

14. Electric Circuit: an electrical device connected so that it provides one or more complete paths for the movement of charges.

15. Series Circuit

16. Schematic Diagram: a graphic representation of an electric circuit or apparatus with standard symbols for the electrical devices.

17. Key Parts of a circuit: