# Physics Principles and Problems 2009

## Chapter 23: Series and Parallel Circuits

### Standardized Test Practice

 1 A circuit includes three resistors in parallel, each with a resistance of 55 Ω. If one of the devices breaks, what is the ratio of the final current to the original current? Need a Hint? A) (1.0K) B) (1.0K) C) 1 D) (1.0K) 2 The diagram shows a circuit with two resistors connected in series. What is the current in the circuit? (7.0K) Need a Hint? A) 0.857 A B) 0.923 A C) 1.02 A D) 1.21 A 3 What is the voltage drop across the 30.0-Ω resistor in the circuit? (7.0K) Need a Hint? A) 25.7 V B) 27.7 V C) 34.3 V D) 60.0 V 4 A string of holiday lights has 15 bulbs with equal resistance. The bulbs are in parallel with each other.. When the entire string of bulbs is connected to a 120-V outlet, the current through each bulb quickly becomes 0.10 A. What is the resistance of each bulb in this situation? Need a Hint? A) 0.013 Ω B) 80 Ω C) 600 Ω D) 1200 Ω 5 The diagram below shows a circuit with three resistors connected in parallel. What is the current through the battery? (10.0K) Need a Hint? A) 0.857 A B) 1.50 A C) 3.00 A D) 10.5 A 6 Which statement correctly describes how an ammeter and a voltmeter should be connected with a resistor? Need a Hint? A) The ammeter should be connected in series; the voltmeter should be connected in parallel. B) The ammeter should be connected in parallel; the voltmeter should be connected in series. C) Both the ammeter and the voltmeter should be connected in parallel. D) Both the ammeter and the voltmeter should be connected in series. 7 Two appliances, a lamp with a resistance of 15.0 Ω and a curling iron with a resistance of 20.0 Ω, are connected in parallel to a 120.0-V source through a 2.00-Ω resistor in series. How much current passes through the circuit when both appliances are on? Need a Hint? A) 10.7 A B) 11.3 A C) 14.8 A D) 15.2 A 8 What is the equivalent resistance in the circuit below? (4.0K) Need a Hint? A) 1.5 Ω B) 12 Ω C) 19 Ω D) 25 Ω 9 A circuit consists of a battery and two 22-Ω resistors in series. The current through the circuit is 0.55 A. A third resistor is then added to the circuit in parallel with the first two resistors. The current through the new branch of the circuit is 0.35 A. What is the resistance of the third resistor? Need a Hint? A) 15 Ω B) 24 Ω C) 28 Ω D) 69 Ω 10 What effect does connecting additional appliances in parallel to a circuit have on the current through that circuit? Need a Hint? A) The total current through the circuit does not change. B) The total current through the circuit decreases. C) The total current through the circuit increases. D) The total current through the circuit may increase or decrease, depending on the properties of the added appliances.