Chapter 25. Current = Rate of flow of charge Unit: A ( Ampere ) 1 A = 1C/s Current flows from high...
-
Upload
clement-mitchell -
Category
Documents
-
view
220 -
download
0
Transcript of Chapter 25. Current = Rate of flow of charge Unit: A ( Ampere ) 1 A = 1C/s Current flows from high...
![Page 1: Chapter 25. Current = Rate of flow of charge Unit: A ( Ampere ) 1 A = 1C/s Current flows from high potential to low potential.](https://reader035.fdocuments.in/reader035/viewer/2022062322/5697bf741a28abf838c7fa1c/html5/thumbnails/1.jpg)
CURRENT, RESISTANCE, AND ELECTROMOTIVE FORCE
Chapter 25
![Page 2: Chapter 25. Current = Rate of flow of charge Unit: A ( Ampere ) 1 A = 1C/s Current flows from high potential to low potential.](https://reader035.fdocuments.in/reader035/viewer/2022062322/5697bf741a28abf838c7fa1c/html5/thumbnails/2.jpg)
CURRENT
Current = Rate of flow of charge Unit: A (Ampere)1 A = 1C/s
Current flows from high potential to low potential
![Page 3: Chapter 25. Current = Rate of flow of charge Unit: A ( Ampere ) 1 A = 1C/s Current flows from high potential to low potential.](https://reader035.fdocuments.in/reader035/viewer/2022062322/5697bf741a28abf838c7fa1c/html5/thumbnails/3.jpg)
TOTAL AMOUNT OF CHARGESuppose a wire carries current I. Find the total charge passing through the wire in time t.
![Page 4: Chapter 25. Current = Rate of flow of charge Unit: A ( Ampere ) 1 A = 1C/s Current flows from high potential to low potential.](https://reader035.fdocuments.in/reader035/viewer/2022062322/5697bf741a28abf838c7fa1c/html5/thumbnails/4.jpg)
CONSERVATION OF CHARGE(KIRCHHOFF’S JUNCTION RULE)
Arrows: Directions of POSITIVE charge flow
We now know that current (in metals) is in fact caused by negatively charged electrons flowing in the opposite direction.
![Page 5: Chapter 25. Current = Rate of flow of charge Unit: A ( Ampere ) 1 A = 1C/s Current flows from high potential to low potential.](https://reader035.fdocuments.in/reader035/viewer/2022062322/5697bf741a28abf838c7fa1c/html5/thumbnails/5.jpg)
POSITIVE OR NEGATIVE CHARGE CARRIERS
![Page 6: Chapter 25. Current = Rate of flow of charge Unit: A ( Ampere ) 1 A = 1C/s Current flows from high potential to low potential.](https://reader035.fdocuments.in/reader035/viewer/2022062322/5697bf741a28abf838c7fa1c/html5/thumbnails/6.jpg)
CURRENT DENSITYCurrent Density: Current per unit areaUnit: A/m2
a b
![Page 7: Chapter 25. Current = Rate of flow of charge Unit: A ( Ampere ) 1 A = 1C/s Current flows from high potential to low potential.](https://reader035.fdocuments.in/reader035/viewer/2022062322/5697bf741a28abf838c7fa1c/html5/thumbnails/7.jpg)
DIRECTION
Left or Right?
I
J
E Right
Right
Right
![Page 8: Chapter 25. Current = Rate of flow of charge Unit: A ( Ampere ) 1 A = 1C/s Current flows from high potential to low potential.](https://reader035.fdocuments.in/reader035/viewer/2022062322/5697bf741a28abf838c7fa1c/html5/thumbnails/8.jpg)
DRIFT VELOCITY
Closing time at the bar
Drift velocity: vd
![Page 9: Chapter 25. Current = Rate of flow of charge Unit: A ( Ampere ) 1 A = 1C/s Current flows from high potential to low potential.](https://reader035.fdocuments.in/reader035/viewer/2022062322/5697bf741a28abf838c7fa1c/html5/thumbnails/9.jpg)
DERIVATION OF DRIFT VELOCITY
![Page 10: Chapter 25. Current = Rate of flow of charge Unit: A ( Ampere ) 1 A = 1C/s Current flows from high potential to low potential.](https://reader035.fdocuments.in/reader035/viewer/2022062322/5697bf741a28abf838c7fa1c/html5/thumbnails/10.jpg)
FIND THE DRIFT VELOCITYGiven n=8.49 × 1028 m-3 for copper, what is the drift velocity of electrons in a copper wire with radius r=900μm and I =17 mA?
![Page 11: Chapter 25. Current = Rate of flow of charge Unit: A ( Ampere ) 1 A = 1C/s Current flows from high potential to low potential.](https://reader035.fdocuments.in/reader035/viewer/2022062322/5697bf741a28abf838c7fa1c/html5/thumbnails/11.jpg)
RESISTANCE
![Page 12: Chapter 25. Current = Rate of flow of charge Unit: A ( Ampere ) 1 A = 1C/s Current flows from high potential to low potential.](https://reader035.fdocuments.in/reader035/viewer/2022062322/5697bf741a28abf838c7fa1c/html5/thumbnails/12.jpg)
OHM’S LAW
![Page 13: Chapter 25. Current = Rate of flow of charge Unit: A ( Ampere ) 1 A = 1C/s Current flows from high potential to low potential.](https://reader035.fdocuments.in/reader035/viewer/2022062322/5697bf741a28abf838c7fa1c/html5/thumbnails/13.jpg)
RESISTOR
![Page 14: Chapter 25. Current = Rate of flow of charge Unit: A ( Ampere ) 1 A = 1C/s Current flows from high potential to low potential.](https://reader035.fdocuments.in/reader035/viewer/2022062322/5697bf741a28abf838c7fa1c/html5/thumbnails/14.jpg)
RESISTIVITY ρ AND CONDUCTIVITY σ
![Page 15: Chapter 25. Current = Rate of flow of charge Unit: A ( Ampere ) 1 A = 1C/s Current flows from high potential to low potential.](https://reader035.fdocuments.in/reader035/viewer/2022062322/5697bf741a28abf838c7fa1c/html5/thumbnails/15.jpg)
RESISTIVITY
![Page 16: Chapter 25. Current = Rate of flow of charge Unit: A ( Ampere ) 1 A = 1C/s Current flows from high potential to low potential.](https://reader035.fdocuments.in/reader035/viewer/2022062322/5697bf741a28abf838c7fa1c/html5/thumbnails/16.jpg)
WHICH HAS THE HIGHER RESISTANCE?
![Page 17: Chapter 25. Current = Rate of flow of charge Unit: A ( Ampere ) 1 A = 1C/s Current flows from high potential to low potential.](https://reader035.fdocuments.in/reader035/viewer/2022062322/5697bf741a28abf838c7fa1c/html5/thumbnails/17.jpg)
OHMIC MATERIAL
![Page 18: Chapter 25. Current = Rate of flow of charge Unit: A ( Ampere ) 1 A = 1C/s Current flows from high potential to low potential.](https://reader035.fdocuments.in/reader035/viewer/2022062322/5697bf741a28abf838c7fa1c/html5/thumbnails/18.jpg)
NONOHMIC MATERIAL, GRAPH
![Page 19: Chapter 25. Current = Rate of flow of charge Unit: A ( Ampere ) 1 A = 1C/s Current flows from high potential to low potential.](https://reader035.fdocuments.in/reader035/viewer/2022062322/5697bf741a28abf838c7fa1c/html5/thumbnails/19.jpg)
POWER
Power: Energy per unit timeUnit: W (Watt)1W=1J/s
![Page 20: Chapter 25. Current = Rate of flow of charge Unit: A ( Ampere ) 1 A = 1C/s Current flows from high potential to low potential.](https://reader035.fdocuments.in/reader035/viewer/2022062322/5697bf741a28abf838c7fa1c/html5/thumbnails/20.jpg)
EXAMPLE
![Page 21: Chapter 25. Current = Rate of flow of charge Unit: A ( Ampere ) 1 A = 1C/s Current flows from high potential to low potential.](https://reader035.fdocuments.in/reader035/viewer/2022062322/5697bf741a28abf838c7fa1c/html5/thumbnails/21.jpg)
KILOWATT-HOUR AND JOULES
Both measure energy1kWh is the amount of energy dissipated by a 1000 Watts light bulb in one hour.Therefore:1kWh = (1000J/s) (3600s)=3.6 × 106 J