Version CIRCUITS holland (9) This print-out should have questions Multiple-choice questions may continue on the next column or page find all choices before answering AP M 99 MC points The power dissipated in a wire carrying a constant electric current I may be written as a function of I, the length l of the wire, the diameter d of the wire, and the resistivity ρ of the material in the wire In this expression, the power P dissipated is directly proportional to which of the following? P d and P ρ only P d only P l, P d and P ρ P l and P ρ only P l only AP M 99 MC 67 points A variable resistor is connected across a constant voltage source Which of the following graphs represents the power P dissipated by the resistor as a function of its resistance R? 6 7 8 9 6 7 8 9 6 7 6 7 8 9 6 7 8 9 6 7 8 9 6 7 8 9 6 7 8 9 AP M 998 MC points A wire of resistance R dissipates power P when a current I passes through it The wire is replaced by another wire with resistance R The power P dissipated by the new wire when the same current passed through it is P = 6P
Version CIRCUITS holland (9) P = P P = P 9 P = P P = P AP B 99 MC (part of ) points A battery with an internal resistance is connected to two resistors in series 6 Ω Ω A X internal resistance What is the emf of the battery? = V = 6 V = V = 8 V = V Ω (part of ) points What is the potential difference across the terminals Y and X of the battery? V YX = 8 V V YX = V V YX = V V YX = 6 V V YX = V 6 (part of ) points What power P internal is dissipated by the Ω Y internal resistance of the battery? P internal = W P internal = 6 W P internal = 8 W P internal = W P internal = 6 W AP M 99 MC 7 8 7 (part of ) points The switch has been open for a long period of time R R V Immediately after the switch is closed, the current supplied by the battery is I = V (R +R ) R R I = I = V R I = I = V R V R +R 8 (part of ) points A long time after the switch has been closed, the current I supplied by the battery is I = V R +R I = V (R +R ) R R C S
Version CIRCUITS holland (9) I = V R I = V R I = AP M 99 MC 7 9 (part of ) points The circuit has been connected as shown in the figure for a long time t t / = 6 µs t t / = µs t t / = 68 µs t t / = 6 µs t t / = 98 µs 6 t t / = µs 8 Ω Ω 7 t t / = 8 µs V Ω 8 µf Ω S 8 t t / = 6 µs 9 t t / = 76 µs t t / = µs What is the magnitude of the electric potential C across the capacitor? C = V C = 8 V C = 6 V C = V C = V 6 C = V 7 C = 6 V 8 C = V 9 C = V C = 9 V (part of ) points Ifthebatteryisdisconnected,howlongdoesit take for the capacitor to discharge to t = e of its initial voltage? AP M 998 MC (part of ) points The following diagram shows part of a closed electrical circuit Ω 7 Ω X 9 Ω Find the electric resistance R XY of the part of the circuit shown between point X and Y R XY = Ω R XY = 6 Ω R XY = Ω R XY = 8 Ω R XY = Ω 6 R XY = Ω 7 R XY = Ω I Y
Version CIRCUITS holland (9) 8 R XY = Ω 9 R XY = 8 Ω R XY = 7 Ω (part of ) points When there is a steady current in the circuit, the amount of charge passing a point per unit time is greater at point X than at point Y greaterinthe9ωresistorthaninthe7ω resistor greater in the Ω resistor than in the 7 Ω resistor greater in the 7 Ω resistor than in the 9 Ω resistor the same everywhere in the circuit AP M 998 MC 6 points A resistor R and a capacitor C are connected in series to a battery of terminal voltage V Which of the following equations relating the current I in the circuit and the charge Q on the capacitor describes this circuit? V Q C IR = V Q C I R = V +QC I R = V C dq dt I R = Q C IR = Which of the following combinations of resistors would dissipate 7 W when connected to a 7 V power supply? 9 Ω 9 Ω 8 Ω 8 Ω 8 Ω 7 Ω Ω 7 Ω 8 Ω 6 Ω 7 Ω 6 Ω Ω 8 Ω Ω 7 Ω AP B 99 MC points Kirchhoff s loop rule for circuit analysis is an expression of which of the following? Conservation of energy Faraday s law Conservation of charge Ohm s law Ampère s law AP B 99 MC 6 6 (part of ) points Consider the circuit AP M 998 MC 7 points
Version CIRCUITS holland (9) a V µf µf c µf µf b R R What is the equivalent capacitance for this network? C equivalent = 7 µf C equivalent = µf C equivalent = 7 µf C equivalent = 7 µf C equivalent = µf 7 (part of ) points What is the charge stored in the -µf lowerright capacitor? Q = µc Q = 7 µc Q =,8 µc Q = 6 µc Q =, µc AP B 99 MC 8 points Consider resistors R and R connected in series R R and in parallel to a source of emf that has no internal resistance How does the power dissipated by the resistors in these two cases compare? It is greater for the series connection Itisdifferent for eachconnection, but one must know the values of R and R to know which is greater It is greater for the parallel connection Itisdifferent for eachconnection, but one must know the values of to know which is greater It is the same for both connections AP M 99 MC 9 9 (part of ) points Consider the system of equivalent capacitors µf µf a B µf µf µf µf Find the equivalent capacitance C ab of the network of capacitors C = µf C = µf C = µf b
Version CIRCUITS holland (9) 6 C = µf µf µf C = 6 µf µf µf Find 6 C = µf 7 C = µf B µf 8 C = µf µf (part of ) points What potential difference must be applied between points a and b so that the charge on each plate of each capacitor will have a magnitude of 6 µc? V ab = V V ab = 9 V V ab = V V ab = 6 V V ab = 8 V 6 V ab = V 7 V ab = V 8 V ab = V AP M 99 MC (part of ) points Consider the following system of equivalent capacitors the equivalent capacitance of the circuit C = µf C = µf C = µf C = µf C = µf 6 C = µf 7 C = µf (part of ) points What potential difference must be applied across the capacitor network so that the charge on each plate of each capacitor will have a magnitude of 6 µc? V ad = 8V V ad = 6V V ad = V V ad = V V ad = V 6 V ad = V 7 V ad = V
Version CIRCUITS holland (9) 7 8 V ad = V AP M 998 MC 6 (part of ) points The following diagram shows part of a closed electrical circuit Ω X Ω Ω Y Ω resistor greater at point X than at point Y greater in the Ω resistor than in the Ω resistor I FindtheelectricresistanceR XY ofthepart of the circuit shown between point X and Y R XY = 9 Ω R XY = Ω R XY = Ω R XY = Ω R XY = Ω 6 R XY = 7 Ω 7 R XY = 7 Ω 8 R XY = 7 Ω 9 R XY = Ω R XY = 9 Ω (part of ) points When there is a steady current in the circuit, the amount of charge passing a point per unit time is the same everywhere in the circuit greater in the Ω resistor than in the Ω resistor greater in the Ω resistor than in the