CrktCT 9 The three light bulbs A B and C are identical How does the brightness of bulbs B and C together compare with the brightness of bulb A A A Total power in B C power in A B Total power in B C power in A C Total power in B C power in A B C V 12V Answer Use P V2 Rtot For bulbs B and C Rtot 2R Total power in B C power in A CrktCT 10 Two light bulbs A and B are connected in series to a constant voltage source When a wire is connected across B as shown the brightness of bulb A A increases B decreases but remains glowing C decreases to zero bulb A goes completely dark no current D remains unchanged Answer Bulb A increases in brightness since the current increases when B is shorted CrktCT 11 A circuit with two batteries is shown below The directions of the currents have been chosen guessed as shown Which is the correct current equation for this circuit A I2 I1 I3 B I1 I2 I3 C I3 I1 I2 D None of these I1 R1 V1 R2 V2 I2 Loop 1 R3 I3 Answer I3 I1 I2 CrktCT 12 I1 I3 R1 V1 R2 I2 Loop 1 V2 R3 I3 Which equation below is the correct equation for Loop 1 A V2 I1R1 I2R2 0 B V2 I1R1 I2R2 0 C V2 I1R1 I2R2 0 D V2 I1R1 I2R2 0 E None of these Answer V2 I1R1 I2R2 0 CrktCT 13 Consider the circuit shown If you want to measure the current thru bulb 3 how should the ammeter be attached Pink 1 A A Yellow 2 V A Blue 4 3 A Green A Pink B Yellow C Green D Blue E Two of the 4 positions can be used to measure bulb3 s current Answer B Yellow CrktCT 14 I In the circuit shown what does the voltmeter read A B C D E 6V 3V 2V 0V Voltmeter will fry 6V 2 6V 2 V Answer 6 V Now you switch the voltmeter over to amp mode But you leave it in the same position in the circuit What does the ammeter read A B C D E 6A 3A 2A 0A Ammeter will fry Answer Ammeter will fry Ideal ammeter has zero internal resistance If you attach an ideal ammeter to a battery you will get infinite A current CrktCT 15 The light bulbs in the circuit are identical When the switch is closed A switch 12 V B 12 V A bulb A glows and bulb B changes brightness B bulb A glows and bulb B stays the same C bulb A does not glow and bulb B changes brightness D bulb A does not glow and bulb B stays the same E Something else happens Answer bulb A does not glow and bulb B stays the same After the switch is closed the voltage drop across bulb A is zero while the voltage drop across B is 12V CrktCT 16 The light bulbs in the circuit are identical When the switch is closed A both go out B both stay the same C the intensity of light bulb B increases D the intensity of light bulb B decreases E both bulbs burn out due to infinite very large current Answer both stay the same CrktCT 17 All batteries shown are identical 1 5 V How do the brightnesses of the bulbs compare Look carefully at the orientation of the batteries A A is brighter B A and B are the same brightness C A is on but B is brighter D A is off so B is brighter E Both bulbs are off Answer A and B are the same brightness since both have the same voltage across them In A two of the three battery voltages cancel B A 0 CrktCT 18 In the circuit shown the two bulbs are identical The switch is suddenly closed What happens to the currents through points A and B A B C D E IA stays same IA increases IA stays same IA increases IA decreases IB decreases IB stays the same IB stays the same IB decreases IB decreases IA A Answer IA increases IB stays the same B IB switch
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