1. The electric potential at a given location in a circuit is the amount of per at that location. The location of highest potential within a circuit is at the { +, ) terminal of the battery. As charge moves through the external circuit from the ( +, ) to the ( +, ) terminal, the charge loses potential energy. As charge moves through the battery, it gains potential energy. The difference in electric Potential between any two locations within the circuit is known as the electric potential difference; it is sometimes called the and represented by the symbol . The rate at which charge moves past any point along the circuit is known as the and is expressed with the unit The diagram at the right depicts an electric circuit in a car. The rear defroster is connected to the 12Volt car battery. Several points are labeled along the circuit. Use this diagram for questions #2tt6. ; 2. Charge owing through this circuit possesses D I of potential energy at D point _. I: 3. The overall effect of this circuit is to convert energy into energy. a. electrical, chemical b. chemical, mechanical c. therInal, electrical (1. chemical, thermal 4. The potential energy of the charge at point A is _ the potential energy at B. a. greater than b. less than c. approximately equal to 5. The + charge gains potential energy as it moves between points _ and _. a. A and B b. B and C c. C and D d. D and A e. none of these 6. The + charge loses potential energy as it moves between points _ and _. a. A and B b. B and C c. C and D d. D and A e. none of these 7. The rate at which energy is delivered to a circuit by the energy source or the rate at which energy is consumed by an electrical device is known as the electric a. current b. potential c. voltage (1. power 8. The 1mit of electric power is the a. Ampere b. Volt c. Watt (1. Ioule 9. Mechanical power (discussed in a previous unit) is the rate at which work is done on an object. Electrical power is the rate at which work is done on a charge (by the battery) or on an electrical device (by the charge). In terms of an equation, it is . . . . (Fill in the niunerator and the denominator.) Power = a. A Watt light bulb uses up I of energy when left on for 1 hour (3600 s). b. A Watt light bulb uses up I of energy when left on for 4 hours. c. A 15UUWatt hair dryer uses up ] of energy when used for 5 min (300 s). d. A 120-Watt fan uses up J of energy when left on for a day. 10. Substitution of other electrical equations ( I = Q/t and AV = I.R and AV = W/Q ) into the power equation yields the following three equations. P = I .AV P = I'. R P = AV2 / R Use these equations to solve the following problems. a. Calculate the resistance of a toaster oven if its power is 800 W when connected to a 110-V outlet. b. Calculate the resistance of the 1000 W microwave oven that gets plugged into to a 110-V outlet. c. The TI-84 calculator uses four 1.5-V batteries and has a power of 0.0008 W. What is the current? 11. The following two circuits consist of a power supply, an ammeter (for measuring current), and a light bulb. Use >, VB Energy? (>) C 12 Power Yolts Supply VC VD D P Watts (> ) Add or Remove B Enerau? VB = VD (=) 12. TRUE or FALSE: A kilowatt-hour is a unit of power.13. Alfredo deDarke often leaves household appliances on for no good reason (at least according to his parents). The deDarke family pays 15c/kilowatt-hour (i.e., $.15/kW.hr) for their electrical energy. Express your understanding of dollar power by filling in the following table. Power Rating Time Energy Used Cost (Watt) (hrs) (kilowatt-hour) $) 60 Watt Bulb 1 0.060 kW . hr 50.009 0 Watt Bulb 4 Ten 60 Watt Bulb 24 50 Watt Bulb $10 7 Watt Night Light 168 The Physics Classroom, 2020 Page 2 Electric Circuits Name: 7 Watt Night Light 8760 14. People often claim that an electrical appliance "uses up electricity." Explain what is actually being "used up" and what becomes of this thing that is being used up. Mathematical Relationships in Circuits Read from Lessons 2 and 3 of the Current Electricity chapter at The Physics Classroom: http://www.physicsclassroom.com/Class/circuits/u912c.html http://www.physicsclassroom.com/Class/circuits/u912d.html http://www.physicsclassroom.com/Class/circuits/u913c.html http://www.physicsclassroom.com/Class/circuits/u913d.html MOP Connection: Electric Circuits: sublevels 5 and 6 1 . Matching: Identify the units on the following electrical quantities by placing a letter in the blank. The unit of charge is the Choices: A. Coulombs The unit of electric potential is the B. Amperes The unit of power is the C. Volts The unit of potential energy is the D. Ohms The unit of current is the E. Joules The unit of resistance is the F. WattsAn electric potential diagram is a useful means of representing the potential of a positive charge as it moves around a circuit. The electric potential of a charge at strategic locations in a circuit is represented on a chart. Points on the circuit where the charge has the highest potential are located highest on the chart; points of lowest potential are located lowest on the charts. At some points on the circuit, charges have approximately the same amount of potential. Construct electric potential diagrams for the following circuits. Label the points- lGiven the circuit at the right with the listed current and resistance values, determine the electric potential at the indicated positions. Note that you are to find the electric potential {or voltage) and NOT the electric potential difference (or voltage drop). VA = V VB = V VC 2 V VD = V V13: V 4. Determine the following quantities for the circuit in question #3 above. PSYW a. The overall power. b. The power of the 6o1'un light bulb. c. The overall resistance. (1. The energy used by the circuit in 10 minutes. Show your work for the following problems. 5. a. Determine the amount of energy used when listening to your 5.0Watt IPod Nano for 10 hours. b. Determine the resistance of the [Pod if it uses a 5.2 Volt battery. c. What quantity of charge passes through the [Pod battery during this 10hr time period? 6. a. Calculate the energy used and current drawn by a ZOOW window fan when plugged into a llUV outlet and left on for an 8hr time period. b. Calculate the energy used and the current drawn by a 3400\"; air conditioner that is wired to a ZEDV circuit and left on for an 8hr time period. 7. A ZUGULW hand dryer in a public bathroom at a zoo runs for 30 seconds per cycle. At a cost of 13 cents per kW I'hr, determine the cost of running the dryer 200 times in a day. What is the annual cost of the hand dryer assuming it is used on average 200 times per day? Calculate the resistance and the current for the hand dryer if it is connected to a 220V circuit