Putting it All Together

Transcription

1 Putting it All Together 1. Vocabulary Review Write the term that correctly completes each statement. Use each term once. ampere electric current resistor battery series connection parallel connection electric circuit short circuit ammeter voltmeter a. The is the flow of charged particles. b. In a(n), there is only one path for the current. c. In a(n), there is more than one path for the current. d. A(n) is the unit of current. e. A(n) is a closed loop in which electrons can move. f. A(n) converts chemical energy to electrical energy. g. A(n) is a device designed to have a specific resistor. h. The occurrence when a circuit forms that has a very low resistance. i. A device used to measure the current in part of a circuit j. A device used to measure the voltage across some part of a circuit 2. A battery with a voltage of 9 V is connected to a lamp. The current flowing in the circuit is 0.30 A. The resistance of the lamp is: 3. If a 200 Ω resistor is connected to a 5 V battery, the current in the circuit will be. 4. Draw a circuit diagram with a resistor, ammeter, and battery. Connect the ammeter in series with the other two components. 5. Draw a circuit diagram with a resistor, battery, and voltmeter. Connect the voltmeter in parallel across the resistor. Draw another circuit diagram showing the voltmeter connected in parallel across the battery. 6. Why does a resistor heat up when an electric current flows through it? 7. Is it OK to connect a 100 V toaster to a 200 V circuit? Why or why not? Explain.

2 8. A current of 0.50 A is carried through a lamp when it is connected to a 120 V source. What is the resistance of the lamp? 9. Why do ammeters have low resistance? 10. When you feel a small electric shock such as the small spark you might experience when touching a metal object on a dry day, does the voltage or the current cause the sensation? 11. Understanding Physics Concepts For each physical quantity on the left, write the letter of the matching unit of measurement on the right. 1. Current 2. Resistance 3. Voltage a. ohm b. ampere c. volt 12. Thinking Critically Refer to the diagram below to answer the following questions: In the diagram, a man is moving grease through a long narrow tank by dropping bowling balls into the grease. The weight of the bowling ball pushes grease along as a continuous flow. When a bowling ball reaches the bottom of the tank, a special valve enables the man to retrieve the ball and lift it up again. This diagram provides a simple model of electricity moving through a circuit with a resistor, with the man acting as a battery or other power source. a. Draw the circuit diagram for a battery connected to a resistor. b. In what way is the man in the diagram similar to the battery in the above circuit? c. Assuming that the grease is so thick that the speed of the bowling ball at the bottom of the tank is zero, what happens to the gravitational potential energy of the bowling ball? d. In what way are the bowling balls similar to electrons? e. In what way are the horizontal tracks similar to connecting wires?

3 13. A circuit is setup as shown in the diagram below. What should the reading on the ammeter be? What should the reading on the voltmeter be? 14. A circuit is set up as shown in the diagram below. What is the resistance of the resistor in the circuit? What should be the reading on the voltmeter? How much power is delivered to the resistor? 15. The current is a series circuit. a. higher at the beginning of c. lower at the beginning of b. the same everywhere in d. changing in 16. If the battery voltage does not change, adding more devices in the series the current. a. sometimes decreases c. sometimes increases b. always decreases d. always increases

4 17. Refer to the circuit diagram below to answer the following 3 questions. A. What type of circuit does the diagram represent? a. A series circuit c. a combination series-parallel circuit b. A parallel circuit d. a tandem circuit B. How many current paths are in this circuit? a. One c. four b. Three d. five C. If the 10 Ω resistor were removed from the circuit, which of the following WOULD NOT be true? a. The voltage across the 20 Ω resistor would be unchanged b. The total voltage in the branches would change c. The total voltage through the generator (battery) would change d. The voltage across the 50 Ω resistor would change 18. Which diagram represents a combined series-parallel circuit in which a 30 Ω resistor and a 75 Ω resistor are connected in parallel to a 125 V power source through a 2 Ω resistor in series?

5 19. Refer to the circuit diagram below to answer questions a-c. a. Insert an ammeter in the circuit that would measure the current of the entire circuit. b. Insert an ammeter in the circuit that would measure the current that flows through the 60 Ω resistor. c. Insert a voltmeter that would measure the voltage across the 10 Ω resistor.