Name ______________________________

Date __________________ Period ______

Circuit Practice: Series Circuits

1. Use your understanding of equivalent resistance to complete the following statements:

a. Two 3-Ω resistors placed in series would provide a resistance that is equivalent to one _____-Ω resistor.

b. Three 3-Ω resistors placed in series would provide a resistance that is equivalent to one _____-Ω resistor.

c. Three 5-Ω resistors placed in series would provide a resistance that is equivalent to one _____-Ω resistor.

d. Three resistors with resistance values of 2-Ω , 4-Ω , and 6-Ω are placed in series. These would provide a resistance that is equivalent to one _____-Ω resistor.

e. Three resistors with resistance values of 5-Ω , 6-Ω , and 7-Ω are placed in series. These would provide a resistance that is equivalent to one _____-Ω resistor.

f. Three resistors with resistance values of 12-Ω, 3-Ω, and 21-Ω are placed in series. These would provide a resistance that is equivalent to one _____-Ω resistor.

2. As the number of resistors in a series circuit increases, the overall resistance __________ (increases, decreases, remains the same) and the current in the circuit __________ (increases, decreases, remains the same).

3. Consider the following two diagrams of series circuits. For each diagram, use arrows to indicate the direction of the conventional current. Then, make comparisons of the voltage and the current at the designated points for each diagram.

4. Three identical light bulbs are connected to a D-cell as shown at the right. Which one of the following statements is true?

a. All three bulbs will have the same brightness.

b. The bulb between X and Y will be the brightest.

c. The bulb between Y and Z will be the brightest.

d. The bulb between Z and the battery will be the brightest.

5. Three identical light bulbs are connected to a battery as shown at the right. Which adjustments could be made to the circuit that would increase the current being measured at X? Circle all that apply.

a. Increase the resistance of one of the bulbs.

b. Increase the resistance of two of the bulbs.

c. Decrease the resistance of two of the bulbs.

d. Increase the voltage of the battery.

e. Decrease the voltage of the battery.

f. Remove one of the bulbs.

6. Three identical light bulbs are connected to a battery as shown at the right. W, X, Y and Z represent locations along the circuit. Which one of the following statements is true?

a. The potential difference between X and Y is greater than that between Y and Z.

b. The potential difference between X and Y is greater than that between Y and W.

c. The potential difference between Y and Z is greater than that between Y and W.

d. The potential difference between X and Z is greater than that between Z and W.

e. The potential difference between X and W is greater than that across the battery.

f. The potential difference between X and Y is greater than that between Z and W.

7. Compare circuit X and Y below. Each is powered by a 12-volt battery. The voltage drop across the 12-ohm resistor in circuit Y is ____ the voltage drop across the single resistor in X.

a. smaller than

b. larger than

c. the same as

8. A 12-V battery, a 12-ohm resistor and a light bulb are connected as shown in circuit X below. A 6-ohm resistor is added to the 12-ohm resistor and bulb to create circuit Y as shown. The bulb will appear ____.

a. dimmer in circuit X

b. dimmer in circuit Y

c. the same brightness in both circuits

9. Three resistors are connected in series. If placed in a circuit with a 12-volt power supply. Determine the equivalent resistance, the total circuit current, and the voltage drop across and current at each resistor.

Circuit Practice: Parallel Circuit

10. As more and more resistors are added in parallel to a circuit, the equivalent resistance of the circuit ____________ (increases, decreases) and the total current of the circuit ____________ (increases, decreases).

11. Three identical light bulbs are connected to a D-cell as shown below. P, Q, X, Y and Z represent locations along the circuit. Which one of the following statements is true?

a. The current at Y is greater than the current at Q.

b. The current at Y is greater than the current at P.

c. The current at Y is greater than the current at Z.

d. The current at P is greater than the current at Q.

e. The current at Q is greater than the current at P.

f. The current is the same at all locations.

12. Three identical light bulbs are connected to a D-cell as shown below. P, Q, X, Y and Z represent locations along the circuit. At which location(s), if any, will the current be ...

a. the same as at X? ________

b. the same as at Q? ________

c. the same as at Y? _______

d. less than at Q? _______

e. less than at P? _______

f. twice that at Z? _______

g. three times that at Y? _______

13. Which adjustments could be made to the circuit below that would decrease the current in the cell? Circle all that apply.

a. Increase the resistance of bulb X.

b. Decrease the resistance of bulb X.

c. Increase the resistance of bulb Z.

d. Decrease the resistance of bulb Z.

e. Increase the voltage of the cell (somehow).

f. Decrease the voltage of the cell (somehow).

g. Remove bulb Y.

14. A 12-V battery, a 12-ohm resistor and a 4-ohm resistor are connected as shown. The current in the 12-ohm resistor is ____ that in the 4-ohm resistor.

a. 1/3

b. ½

c. 2/3

d. The same

e. 1.5 times

f. Twice

g. Three times

h. Four times

15. A 12-V battery , a 12-ohm resistor and a 4-ohm resistor are connected as shown. The voltage drop across the 12-ohm resistor is ____ that across the 4-ohm resistor.

a. 1/3

b. ½

c. 2/3

d. The same as

e. 1.5 times

f. Twice

g. Three times

h. Four times

16. A 12-V battery and a 12-ohm resistor are connected as shown in circuit. A 6-ohm resistor is added to the 12-ohm resistor to create circuit Y as shown. The voltage drop across the 6-ohm resistor in circuit Y is ____ that across the resistor in X.

a. larger than

b. smaller than

c. the same as

17. Use your understanding of equivalent resistance to complete the following statements:

a. Two 6-Ω resistors placed in parallel would provide a resistance that is equivalent to one _____-Ω resistor.

b. Three 6-Ω resistors placed in parallel would provide a resistance that is equivalent to one _____-Ω resistor.

c. Three 8-Ω resistors placed in parallel would provide a resistance that is equivalent to one _____-Ω resistor.

d. Three resistors with resistance values of 2-Ω, 4-Ω, and 6-Ω are placed in parallel. These would provide a resistance that is equivalent to one _____-Ω resistor.

e. Three resistors with resistance values of 5-Ω, 6-Ω, and 7-Ω are placed in parallel. These would provide a resistance that is equivalent to one _____-Ω resistor.

f. Three resistors with resistance values of 12-Ω, 6-Ω, and 21-Ω are placed in parallel. These would provide a resistance that is equivalent to one _____-Ω resistor.

18. Based on your answers to the above question, complete the following statement: The overall or equivalent resistance of three resistors placed in parallel will be _____.

a. greater than the resistance of the biggest R value of the three.

b. less than the resistance of the smallest R value of the three.

c. somewhere in between the smallest R and the biggest R value of the three.

d. ... nonsense! No such generalization can be made. The results vary.

19. Three resistors are connected in parallel. If placed in a circuit with a 12-volt power supply. Determine the equivalent resistance, the total circuit current, and the voltage drop across and current in each resistor.