1. Electric Current

2. There are 72 names of French mathematicians, engineers and scientists on the side of the Eiffel tower

3. Electric Current (I) The flow of electric charge Unit- Amperes (Symbol A) An Ampere - 1 coulomb of charge second (1 coulomb = 6.24 billion billion electrons) Measured using an ammeter

4. Electric Current When no electricity is applied…free electrons (conducting electrons) are always moving in random motion But when the switch is closed the free electrons of the conductor are forced to drift toward the positive terminal under the influence of the electric fieldfree electronspositive

5. Resistance

6. Resistance- helps to control the amt of current Opposition to the passage of an electric current through that conductor.electric current Unit- ohm (Ω)ohmΩ

7. Resistance (R) The resistance of an object depends primarily on 3 factors: 1) What the material is made of Place in order of least resistance the following materials: Aluminum, gold, silver, glass, copper Silver Copper Gold Aluminum Glass

8. The resistance of an object depends primarily on 3 factors: 2) It’s thickness A thick copper wire has lower resistance than an otherwise-identical thin copper wire.

9. Not a good idea 3) It’s length For example- a long copper wire has higher resistance than a short copper wire.

10. Relationship between voltage, current and resistance

11. Ohm’s Law

12. Current = Voltage Resistance Current (amps)= Voltage (volts) Resistance (ohms) The greater the voltage the _ the current The greater the resistance the _ the current

14. Resistance A typical lightbulb has a resistance of 100 Ώ An iron or toaster has a resistance of 15-20 Ώ The lower resistance permits a large current, which produces a considerable amount of heat