1. Physics 12 Mr. Jean November 23 rd, 2011

2. The plan: Video clip of the day Review of last day’s material Series circuits Parallel circuits Solutions to Yesterday’s HW Coulomb’s Law Assignment Returned Hopefully tomorrow’s class –(Resistance in a wire)

3. The rest of the year: Chapter #16 – Magnetics & Motors –(1 to 2 weeks) Chapter #17 – Special Relativity –(1 to 2 weeks) Chapter #20 – Radio Activity –(1 to 2 weeks) Chapter #21 – Nuclear Energy –(1 to 2 weeks)

4. Semi-conductors: These are the devices that are at the heart of the microelectronic revolution. These objects have single handily ushered in the information age. The memory located in your ipod nano (16gig), 60 years ago would have required a building the size of the Empire State Building to store.

5. Super Conductors: This occurs in most materials at temperatures just about absolute zero. Why are these things awesome. These items loose ALL electric resistance. There is no energy lost in this situation.

6. Super Conductors Once we finally understand how to make these at a more common (Earthly) temperature this will be a significant change to how we use, transport and store energy. Super Conductors can and will make many radical changes in our future.

7. Electric Power: This represents the amount of power in a system. P = IV P = power in watts (W) (W = A*V) I = Current in amps (A) V = potential difference (V) 1 W = 1J / 1s

8. Resistance of a Conductor: (Through a wire) R = resistance in Ohms (Ω) p = factor of resistivity in Ohms metre (Ω*m) L = length of the conductor in metres (m) A = cross sectional area of the wire metres squared (m 2 ). Thickness of the wire.

9. Lab Work: Today we will try a mini-lab to see how our electric tools work. Page 709

10. Procedure: 1) Use the resistance in a wire formula to solve for the factor of resistivity. 2) Measure wires lengths. 3) Run the DC power supply LOW. The less current you let through the DC power supply the less heat / danger.

11. Wire Description ThicknessLength

12. Let’s get the circuits set up: Using the image on P. 709, Let’s get all of these working Warning! WIRE GETS HOT!!!!!!!! HOT HOT HOT HOT HOT….. HOT.