Self-Test: Electric Circuits Test #1
Suggested Time: 65 minutes

1. Which household electrical appliance consumes the least energy in a typical month?
 A. Stove B. Dryer C. Clock D. Refrigerator

2. What is the power output of the 6.0 ohm resistor in the diagram?

 A. 36 W B. 54 W C. 90 W D. 150 W

3. A 12 V power supply is connected to an 8.0 ohm resistor for 50 s. How much charge passes through the resistor?
 A. 1.9 C D. 75 C B. 900 C C. 4800 C

4. Which of the following correctly labels arrows 1 and 2 and polarities X and Y in the circuit below?

5. Switch S is originally open as shown in the circuit below.

How does the current through resistors R 1 and R 2 change when switch S is closed?

6. In which of the following circuits is the voltmeter placed correctly to measure the terminal voltage of the battery, and the ammeter placed correctly to measure the current through the light bulb ?

7. What is the current leaving the battery in the circuit below?

 A. 1.3 A B. 1.5 A C. 2.0 A D. 4.0 A

8. What is the power dissipated in the unknown resistor R x in the circuit below?

 A. 0.3 W B. 1.4 W C. 1.7 W D. 2.0 W

9. Calculate the current through the 6.0 ohm resistor in the circuit shown.

 A. 1.1 A B. 2.0 A C. 4.0 A D. 6.7 A

10. In the following circuit, determine the value of resistor R.

 A. 3.2 ohms B. 5.2 ohms C. 9.0 ohms D. 23 ohms

11. What is the voltage, V, of the power supply shown in the circuit?

 A. 24 V B. 52 V C. 72 V D. 96 V

12. Two identical resistors connected in series have a total power output of 400 W. Assuming V and R remain constant, what would the total power output be when the resistors are re-connected in parallel?

 A. 200 W B. 400 W C. 800 W D. 1600 W

13. A battery whose emf is 6.0 V is connected to a 2.0 ohm resistor. The voltage drop across the 2.0 ohm resistor is 5.0 V. What is its internal resistance?
 A. 0.40 ohms B. 1.7 ohms C. 2.4 ohms D. 2.5 ohms

14. A 2.50 W device requires 1.20 V to operate properly. A 1.45 V cell, with internal resistance r, is used to power this device. What value of r enables the cell to provide 1.20 V to the device?

 A. 0.120 ohms B. 0.145 ohms C. 0.576 ohms D. 0.841 ohms

15. a) Find the current in the 8.0 ohm bulb shown below. (5 marks)

b) The 3.0 ohm bulb is removed from the circuit so that only 3 bulbs remain. The 8.0 ohm bulb will now: (Circle one) (1 mark)

 A. be dimmer. B. be brighter. C. remain the same.

16. Consider the circuit shown in the diagram below.

a) What is the total resistance of the circuit? (3 marks)

b) What is the current through the 100 ohm resistor? (2 marks)

c) What is the power dissipated in the 100 ohm resistor? (2 marks)

17. Consider the circuit shown below.

a) What is the current through the 7.0 ohm resistor? (5 marks)

b) How much charge flows through the 7.0 ohm resistor in a 30 s interval? (2 marks)

18. The circuit shown in the diagram below consists of a 9.00 V battery and a 3.50 W light bulb.

a) If a current of 0.400 A leaves the battery, what is the internal resistance, r, of the battery? (5 marks)

b) The light bulb is now replaced by a lower resistance (brighter) light bulb. The terminal voltage will now be (circle one ) (1 mark)

i) less than before.

ii) the same as before.

iii) greater than before.

c) Use principles of physics to explain your answer to part (b). (3 marks)

19. What is the power dissipated in the 33 ohm resistor in the circuit shown below? (7 marks)
20. The cell shown delivers a 1.50 A current to the external circuit and has a terminal voltage of 2.70 V.

a) What is the emf of the cell? (4 marks)

b) The 1.80 ohm external resistance is replaced by other resistors and the current and terminal voltage are measured in each case. Which graph best represents terminal voltage V T versus current I as these resistors are changed? (2 marks)