Physics CP
Circuits Final Review
1.
Why do electrons (not protons) make up the flow through a metal wire? 2. Define current. 3. Describe the energy transformations that occur as current flows through a circuit which has a battery, a resistor, and a light bulb. 4. What is potential difference? What is another name for potential difference? 5. Define resistance. 6. What are the units for each of the following? Current: __________________ Resistance: __________________ Charge: __________________ Power: __________________ 7. What are the symbols used for the following in a circuit? a. Wire d. Battery or source b. Open switch e.
Light bulb| c.
f.
Resistor Closed switch 8.
What is the main difference between parallel and series circuits? Draw a diagram of each. Label the source, the potential difference across the battery, the path, and the resistance. 9. What is constant at every point in a series circuit? 10. Draw a schematic diagram for each of the circuits below: a. A 12 V battery is connected to a 5 Ω resistor. b. A 12 V battery is connected to two 10 Ω resistors connected in series to each other. c. A 9.0 V battery is connected to a 10 Ω resistor connected in parallel to another 10 Ω resistor. 11. What happens to the current in the other light bulbs in a series circuit if one bulb burns out? 12. Are household circuits normally wired in series or in parallel? Why? 13. What happens to the light intensity of each bulb in a series circuit when more bulbs are added to the circuit? 14. What happens to the current in the other light bulbs in a parallel circuit if one bulb burns out? 15. Which has the greater resistance, a thick wire or a thin wire of the same length? 16. When the equivalent resistance of a circuit is doubled, and no other changes occur, what effect does this have on the current in the circuit? 17. The headlights of a typical car are powered by a 12 V battery. What is the resistance of the headlights if they draw a 3.0 A of current when turned on? 18. What is the current in a 20 Ω resistor connected across a voltage of 120 V? 19. Calculate the equivalent resistance for each of the following circuits. a. A series circuit containing 10 V battery and 3 lamps, each carrying a resistance of 3 ohms b. A parallel circuit containing a 10 V battery and 3 lamps each carrying a resistance of 3 ohms 20. Which of the two circuits above will draw more current from the battery? 21. How much current is needed to operate a clock radio that uses 80 W of power from your household circuit at 120V? 22. Complete the tables for each of the following circuits. Find the V, I, R and P values (total, A, B) for the following circuit. 90 Ω 60
120V 1466.64 A
80 V 8 Ω 16 Ω B 24 Ω