What++do+you+know

**Check Your Understanding**
1. 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).

2. 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.

3. 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?

4. Which adjustments could be made to the circuit below that would decrease the current in the cell? List 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.

5. 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. 1/2 || c. 2/3 ||  ||
 * d. the same as |||| e. 1.5 times ||
 * f. twice |||| g. three times ||
 * h. four times ||  ||   ||

6. 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. 1/2 || c. 2/3 ||  ||
 * d. the same as |||| e. 1.5 times ||
 * f. twice |||| g. three times ||
 * h. four times ||  ||   ||

7. 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

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

a. Two 6- resistors placed in parallel would provide a resistance which is equivalent to one _- resistor. b. Three 6- resistors placed in parallel would provide a resistance which is equivalent to one _- resistor. c. Three 8- resistors placed in parallel would provide a resistance which is equivalent to one _- resistor. d. Three resistors with resistance values of 2-, 4- , and 6- are placed in parallel. These would provide a resistance which is equivalent to one _- resistor. e. Three resistors with resistance values of 5-, 6- , and 7- are placed in parallel. These would provide a resistance which is equivalent to one _- resistor. f. Three resistors with resistance values of 12-, 6- , and 21- are placed in parallel. These would provide a resistance which is equivalent to one _- resistor.

9. Based on your answers to the question above, 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.

10. Three resistors are connected in parallel. If placed in a circuit with a 12-volt power supply. Determine the equivalent resistance, t

**Check Your Understanding**
1. 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).

2. 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.

3. 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?

4. Which adjustments could be made to the circuit below that would decrease the current in the cell? List 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.

5. 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. 1/2 || c. 2/3 ||  ||
 * d. the same as |||| e. 1.5 times ||
 * f. twice |||| g. three times ||
 * h. four times ||  ||   ||

6. 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. 1/2 || c. 2/3 ||  ||
 * d. the same as |||| e. 1.5 times ||
 * f. twice |||| g. three times ||
 * h. four times ||  ||   ||

7. 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

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

a. Two 6- resistors placed in parallel would provide a resistance which is equivalent to one _- resistor. b. Three 6- resistors placed in parallel would provide a resistance which is equivalent to one _- resistor. c. Three 8- resistors placed in parallel would provide a resistance which is equivalent to one _- resistor. d. Three resistors with resistance values of 2-, 4- , and 6- are placed in parallel. These would provide a resistance which is equivalent to one _- resistor. e. Three resistors with resistance values of 5-, 6- , and 7- are placed in parallel. These would provide a resistance which is equivalent to one _- resistor. f. Three resistors with resistance values of 12-, 6- , and 21- are placed in parallel. These would provide a resistance which is equivalent to one _- resistor.

9. Based on your answers to the question above, 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.

10. 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.