2. ELECTRICI TY PART 2, VOLTAGE AND CURRENT

3. VOLTAGE AND CURRENT  Electric charges have ELECTRICAL POTENTIAL ENERGY Depends where they are in the electric fieldDepends where they are in the electric field HIGH POTENTIAL ENERGY LOW POTENTIAL ENERGY HIGH POTENTIAL ENERGY LOW POTENTIAL ENERGY

4. VOLTAGE AND CURRENT Potential energy decreases as the charge moves in response to the fieldPotential energy decreases as the charge moves in response to the field Distance Electrical Potential Energy HIGH POTENTIAL ENERGY LOW POTENTIAL ENERGY

5. VOLTAGE AND CURRENT Potential energy decreases as the charge moves in response to the fieldPotential energy decreases as the charge moves in response to the field Distance Electrical Potential Energy HIGH POTENTIAL ENERGY LOW POTENTIAL ENERGY

6. VOLTAGE AND CURRENT  How do you increase the Electrical Potential Energy?  CHANGE THE DISTANCE!

7. VOLTAGE AND CURRENT IIIIn electricity, Potential Energy is referred to as Potential Difference (the difference in the location of the charge). PPPPotential Difference = Volts (voltage)  SI Unit THE FORCE THAT IS PUSHING THE ELECTRONS. THIS VOLTAGE (FORCE) ALLOWS ELECTRICITY TO FLOW, LIKE WATER FLOWING DOWNHILL.

8. Volts = Change in Potential Energy (Joules) Charge (Coulombs) Volts = J / C

9. VOLTAGE AND CURRENT: Batteries  Batteries have 2 terminals: PositivePositive NegativeNegative  There is a Potential Difference (Voltage) between the terminals.

10. VOLTAGE AND CURRENT: Batteries  There is a Potential Difference (Voltage) between the terminals. This difference pushes the electrons to flow.This difference pushes the electrons to flow.  Potential Difference is Normally = 1.5 V

11. VOLTAGE AND CURRENT: Batteries  A VOLTAGE SETS CHARGES IN MOTION This allows electrons to flow from the positive terminal to the negative. TERMINAL S When you turn on a switch, the terminals of a battery become connected thru the light bulb.

12. VOLTAGE AND CURRENT: Batteries  When charges are pushed from high potential energy to low, an ELECTRICAL CURRENT is produced. 1.5 Volts

13. VOLTAGE AND CURRENT  CURRENT = the rate at which charges move through a conductor.  SI Unit  Ampere (amp)  1 Ampere = 1 Coulomb/second

14. VOLTAGE AND CURRENT CURRENT IN DIFFERENT MATERIALS  METALS = electrons  GASES AND LIQUIDS = positive & negative  OUR BODY = mostly positive (same as Conventional Current)

15. VOLTAGE AND CURRENT: Resistance RESISTANCE: the opposition to the flow of a current.  Caused by INTERNAL FRICTION.  A resistor SLOWS the current (flow of charges).

16. ex: LIGHT BULBS  They’re all designed for 120 Volts from the wall.  But there are many different Watts. 40 W = dim40 W = dim 65 W = medium65 W = medium 100 W = bright100 W = bright VOLTAGE AND CURRENT: Resistance

17.  Watts tell the amount of RESISTANCE in the filament  LOW Watts = HIGH Resistance = DIM (low) light  HIGH Watts = LOW Resistance = BRIGHT (high) light VOLTAGE AND CURRENT: Resistance

18. WHAT AFFECTS RESISTANCE??????  Length – longer = more resistance  Cross-section – smaller = more resistance  Temperature – hotter = more resistance