1. Previous Stuff

2. more dc circuits
February 15, 2010

3. Which diagram ain’t right?
A B C

4. Which bulbs in the diagram will light?
B C
All lights will light.
A and B will light
A and C will light
B and C will light
None of these answers are correct.
It is the same diagram that is on the handout.

5. A B A I(A)=I(B) B I(A)<I(B) C I(A)>I(B) D None of the above
A steady current flows through the wire shown below.
At one point, the wire suddenly narrows. Which of the
following is correct? I
A B
A I(A)=I(B)
B I(A)<I(B)
C I(A)>I(B)
D None of the above

6. Which bulb do you think is brighter?A B C A B C
All the same

7. A current I flows through a device. The difference in potential
from one side of the device to the other is V. How much POWER
is dissipated in the device?

8. Resistance
February 17, 2010
Resistivity
2/17/2010

9. Measuring Voltage
Set to proper scale
Resistivity
2/17/2010

10. Measure current
Set to proper scale
Resistivity
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11. But First … a few clicks
Resistivity
2/17/2010

12. Which lamp is brighter? A
R1 on the left
R2 on the right
Both the same

13. Where is the current largest?
A Point A
B Point B
C Point C
D They are all the same B C A
Resistivity
2/17/2010

14. CURRENT IS NEVER USED UP!
Resistivity
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15. REMEMBER -
Resistivity
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16. Which bulb is brighter?
R1 on the top
R2 on the bottom
Both the same

17. A Bulb A is Brighter B Bulb B is brighter C Both are the same
The two batteries and all of the resistors (light bulbs) have the same values. Which light bulb is brighter?
A Bulb A is Brighter
B Bulb B is brighter
C Both are the same BB A B

18. which has more current? A B C They are the same.
Normal Wire High Resistance Wire (W) A B
C They are the same.
Resistivity
2/17/2010

19. which has more current? A B C They are the same.
Normal Wire High Resistance Wire (W) A B
C They are the same.
Resistivity
2/17/2010

20. which has more current? A B C They are the same.
Normal Wire High Resistance Wire (W) A B
C They are the same.
Resistivity
2/17/2010

21. Resistivity
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22. Resistance
February 17, 2010
Resistivity
2/17/2010

23. Get Moving on these *@&^ing WebAssigns!
Resistivity
2/17/2010

24. What? A Quiz? Noooo…
Resistivity
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25. which has more current? A B C They are the same.
Normal Wire High Resistance Wire (W) A B
C They are the same.
Resistivity
2/17/2010

26. Resistance increases with length.
Resistivity
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27. which has more current? A B C They are the same.
Normal Wire High Resistance Wire (W) A B
C They are the same.
Resistivity
2/17/2010

28. which has more current? A B C They are the same.
Normal Wire High Resistance Wire (W) A B
C They are the same.
Resistivity
2/17/2010

29. Resistance inverse to area.
r is resistivity units=W-m
1/r=s=conductivity
r is a property of the material
Resistivity
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30. Resistivity W-m
Resistivity
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31. Idea: What stays the same?? VOLUME!
A wire has a resistance of R Ω. It is melted down, and from the same volume of metal a new wire is made that is two times longer than the original wire. What is the resistance of the new wire?
Idea: What stays the same??
VOLUME!
Resistivity
2/17/2010

32. What is the resistance A-b?
Resistivity
2/17/2010

33. That’s why you pay tuition .. isn’t it??
Resistivity
2/17/2010