1 A 60-W light bulb operating on a 120-volt household circuit has a resistance closest to

Transcription

1 Slide 1 / 31 1 A 60-W light bulb operating on a 120-volt household circuit has a resistance closest to A 60 Ω B 120 Ω C 240 Ω D 180 Ω E 360 Ω

2 Slide 2 / 31 2 Which of the following is equivalent to the unit of electrical resistance? A C/V B V/A C A/V D V/C E C/J

3 Slide 3 / 31 3 A copper wire has a length L and cross-sectional area A. Another copper wire has a length of 2L and cross-sectional area 4A. What is the ratio of the resistivity of the second wire to the resistivity of the first one? A 1/2 B 1/4 C 2/1 D 4/1 E 1/1

4 Slide 4 / 31 4 If E is the electric field strength and J is the electric current density, what is the ratio of E/J? A Resistance B Resistivity C Voltage D Current E Work

5 Slide 5 / 31 5 Two tungsten wires with different cross-sectional areas and currents are shown on the diagram. Current I has a cross-sectional are A and runs an electric current I. Current II has a cross-sectional are 2A and runs an electric current 4I. What is the ration of drift velocity of particles in the second wire to that in the first one? A 2/1 B 1/2 C 4/1 D 1/4 E 1/1

6 Slide 6 / 31 6 The following graphs represent the resistivity as a function of absolute temperature. Which of the graphs shows the resistivity change of a metallic wire? A B C D E

7 Slide 7 / 31 7 An electric current of 1 A flows through a circuit. The part of the circuit contains a 12 V battery with an internal resistance of 2 Ω. What is the voltmeter reading? A 4 V B 8 V C 10 V D 12 V E 16 V

8 Slide 8 / 31 8 An electric current of 2 A flows through a circuit. The part of the circuit contains a 6 V battery with an internal resistance of 0.5 Ω. What is the voltmeter reading? A 3 V B 4 V C 5 V D 6 V E 7 V

9 Slide 9 / 31 9 An ammeter with an internal resistance of 3.6x10-3 Ω is design to measure the maximum current of 0.2 A (full-scale-deflection). It was predicted that the maximum current in the circuit is 2 A. What must the shunt resistance be and how it has to be connected to the ammeter in order to measure the current in the given circuit? A Ω in parallel B in series C Ω in parallel D Ω in series E Ω in parallel

10 Slide 10 / A voltmeter with an internal resistance of 20 Ω is design to measure the maximum voltage of 2 V (fullscale-deflection). It was predicted that the maximum voltage in the circuit is 120 V. What must the shunt resistance be and how it has to be connected to the voltmeter in order to measure the voltage in the given circuit? A 11,800 Ω in series B 11,800 Ω in parallel C 1,180 Ω in series D 1,180 Ω in parallel E 118,000 Ω in series

11 Slide 11 / Five different electric circuits are connected to the same battery with negligible resistance. Which circuit has the least current through the battery? A B C D E

12 Slide 12 / Five different electric circuits are connected to the same battery with negligible resistance. Which circuit produces the greatest power dissipation? A B C D E

13 Slide 13 / The emf of a battery is 6 V. When the battery delivers a current of 0.5 A to the external circuit, the potential difference between the terminals of the battery is 5.8 V. The internal resistance of the battery is A 0.4 Ω B 4 Ω C 0.6 Ω D 6 Ω E 2 Ω

14 Slide 14 / A wire is connected to a battery of a constant voltage and negligible internal resistance. By decreasing which of the following we can increase the power dissipated in the wire? A L only B d only C L and ρ only D d and ρ only E ρ only

15 Slide 15 / Two resistors with resistance 3 Ω and 2 Ω respectively are connected in series with a 12 V battery. The current in the circuit is 2 A. What is the internal resistance? A 1 Ω B 2 Ω C 3 Ω D 0.5 Ω E 0.2 Ω

16 Slide 16 / Two resistors with resistance of 30 Ω and 60 Ω respectively are connected in parallel with a 6 V battery. The current in the circuit is 0.25 A. What is the internal resistance? A 1 Ω B 2 Ω C 3 Ω D 4 Ω E 5 Ω

17 Slide 17 / Which of the following graphs represents the current as a function of resistance? A B C D E

18 Slide 18 / A rheostat is connected across a battery with a constant voltage. Which of the following graphs represents the power P dissipated by the rheostat as a function of its resistance R? A B C D E

19 Slide 19 / Three identical resistors are connected to each other in four different combinations. Which of the given circuits has the greatest resistance? I II III IV A Only I B Only II C Only III D Only IV E II and IV

20 Slide 20 / A wire of resistance R dissipates power P when a current I passes through it. The wire is replaced by another wire with resistance 3R. The power dissipated by the new wire when the same current passes through it is A P/9 B P/3 C P D 3P E 6P

21 Slide 21 / The circuit in the diagram above contains three identical light bulbs connected as shown. Initially, a switch connected to light bulb I is closed. Which of the following is correct about brightness of light bulb II and III is correct when the switch is open? Bulb II Bulb III A Gets brighter Gets dimmer B Gets dimmer C Gets brighter D Gets dimmer E Goes out Gets brighter Gets brighter Gets dimmer Gets brighter

22 Slide 22 / What is the current in the circuit above? A 4 A B 2 A C 1 A D 0.5 A E 0.25 A

23 Slide 23 / What the potential difference across the 2 Ω resistor in the circuit above? A 1 V B 2 V C 4 V D 6 V E 18 V

24 Slide 24 / The power dissipated in 6 Ω resistor in the circuit above is close to A 10.7 W B 5.3 W C 24.5 W D 37.2 W E 43.4 W

25 Slide 25 / Which of the following is true about the current through resistor R and charge in the capacitor, immediately after the switch is closed? Current I Charge Q A Zero B Maximum C Zero D Maximum Maximum Zero Zero Maximum E Stays unchanged Stays Unchanged

26 Slide 26 / Which of the following is true about the current through resistor R and charge in the capacitor, when the switch is closed for a long time? Current I A Zero B Maximum Charge Q Maximum Zero C Zero D Maximum E Stays unchanged Zero Maximum Stays unchanged

27 Slide 27 / A circuit is connected to a 9 V battery with a net resistance of 40.5 Ω. How much energy is dissipated by the circuit in time interval of 1 min? A 120 J B 240 J C 360 J D 60 J E 30 J

28 Slide 28 / A resistor R = 1x10 6 Ω, a capacitor C = 1 nf are connected in series with a battery V and switch S. What is the time constant of the circuit? A 10-6 s B 10-3 s C 10-9 s D 10 6 s E 10 3 s

29 Slide 29 / In order to measure the current and voltage through a circuit how must an ammeter and voltmeter be connected to a circuit? Ammeter A in parallel B in parallel C in series D in series E none from the above Voltmeter in series in parallel in series in parallel none from the above

30 Slide 30 / A battery with internal resistance R and an electromotive force ε supplies a current I to a light bulb of resistance r. The power dissipated by the circuit is A ε 2 /(R+r) B (ε-ir) 2 /R C (ε-ir) 2 /(R+r) D ε 2 /R E (ε+ir) 2 /(R+r)

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