1. Reading Quiz
Which will draw more current, connecting a 9 volt battery in a circuit with a 1 Ohm resistance or with a 100 Ohm resistance?
1 Ohm
100 Ohms
Same current for both

2. Physics Help Center NEXT EXAM Wednesday April 7th @7pm to 9pm
Room 237 Physics Building: 8am to 5:30pm
Ask for help from graduate students on homework and exams
Can enter solutions on the computers in the room to check your solution.
NEXT EXAM
Wednesday April to 9pm
Chapters 10,11,12,13,14,15

3. Summary of electric circuits:
The amount of current is the same at every place in a series circuit; I=q/t.
The power provided by the battery (P=IDV) is exactly equal to the power dissipated in the resistors (P=I2R).
Ohm’s Law applies to resistors: DV=IR
Series circuit: effective R = R1 + R2 + R3
Parallel circuit: effective R is
Charge is conserved
Current is conserved
The voltage drops around a circuit is zero

4. Question 1
How much current I runs through this circuit?
A Amps
B A
C A
D A
E A
1 W
1.5 V
2 W
Choose the answer closest to your result.

5. Question 2
How much current I is generated by the battery?
A Amps
B A
C A
D A
E A
2 W
1 W
1.5 V
Choose the answer closest to your result.

6. Question 3
What is the voltage drop across the 2 Ohm resistor?
Zero
The same as the drop across the other resistor.
More than across the other resistor.
Less than across the other resistor.
2 W
1 W
1.5 V

7. V A B
switch +
Question 4:
This circuit has 2 identical light bulbs. After the switch is closed,
A is brighter than B.
A is dimmer than B.
A & B are equally bright, but dimmer than A was before.
A & B are equally bright, but brighter than A was before.
A & B are equally bright, and the same as A was before.

8. Question 5:
Light bulbs A, B, & C are identical. After the switch is closed, V A B
switch + C
A. A & C both get brighter.
B. A & C both get dimmer.
C. A is brighter, and C is dimmer.
A is dimmer, and C is brighter.
A & C stay the same.

9. For three resistors in parallel, choose the correct statement:
Question 6
For three resistors in parallel, choose the correct statement:
A. The current and the voltage across all three are the same.
B. The voltage drop and the power dissipated across all three are the same.
C. The energy given up per electron is the same for all three.
D. The current through one resistor is the same as the current through the battery.
EMF
volts 1 2 3

10. By placing electrical items in series they receive the same current
By placing all electric items in parallel they receive the same voltage
Fig
By placing electrical items in series they receive the same current

11. A volt meter has a high resistance so take very little current
Fig
A volt meter has a high resistance so take very little current

12. Fig
Fig
An Amp meter has very little resistance so take very little voltage

13. Question 14
If R1=10 ohms, R2=5 ohms and R3=10 ohms what is the total resistance of the circuit?
Fig. 13.p272g

14. Energy source => Potential Energy => Kinetic Energy => Heat
Power = Energy/unit time
P=V * I
P= (I*R) *I= I2 R
Units of Power
WATTS = Joules/second
Note: Energy = power * time
We purchase electrical energy by the Kilowatt-hr

15. If the resistance of the light is 20 ohms what is the power given off by the light?
If the light were to be on for 24 hours how much energy would be used up?

16. Summary 5
Fig. 13.p271b

17. Fig
Fig

18. B. What is the current that flows in this circuit at point B?
1.)288 amps
2.) 1.5 amp
3.) 0.1 amp
4.) 0.5 amp
5.) 0.03 amps
Fig. 13.p274b

19. By placing electrical items in series they receive the same current
By placing all electric items in parallel they receive the same voltage
Fig
By placing electrical items in series they receive the same current