# College Physics Study Set 7

Physics & Astronomy

## Quiz 17 : Current and Resistance Study Flashcards  Looking for Introductory Physics Homework Help?

## Quiz 17 :Current and Resistance

Question Type  How long is a wire made from 100 cm3 of copper if its resistance is 8.5 ohms? The resistivity of copper is 1.7 * 10-5 W·m.
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A

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Choose question tag  Materials having resistance changes as voltage or current varies are called:
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C

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Choose question tag  The number density of conduction electrons in a metal can be found from the density r of the metal, the mass per mole M of the metal, the number of conduction electrons per metal atom, and Avogadro's number NA.If we assume one conduction electron per atom, which of the following gives the number density of conduction electrons for a given metal?
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B

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Choose question tag  Two wires with the same resistance have the same diameter but different lengths.If wire 1 has length L1 and wire 2 has length L2, how do L1 and L2 compare if wire 1 is made from copper and wire 2 is made from aluminum? The resistivity of copper is 1.7 * 10-5 W·m and the resistivity of aluminum is 2.82 * 10-5 W·m.
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Choose question tag  A flashlight bulb operating at a voltage of 4.5 V has a resistance of 8.0 W.How many electrons pass through the bulb filament per second (e = 1.6 * 10-19 C)?
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Choose question tag  The current in an electron beam in a cathode-ray tube is measured to be 70 µA.How many electrons hit the screen in 5.0 s? (e = 1.6 * 10-19 C)
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Choose question tag  The unit of electric resistance, the ohm, is equivalent to which of the following?
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Choose question tag  If a certain resistor obeys Ohm's law, its resistance will change:
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Choose question tag  Two cylindrical resistors are made of the same material and have the same resistance.The resistors, R1 and R2, have different radii, r1 and r2, and different lengths, L1 and L2.Which of the following relative values for radii and lengths would result in equal resistances?
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Choose question tag  You measure a 25.0-V potential difference across a 5.00-W resistor.What is the current flowing through it?
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Choose question tag  If a metallic wire of cross sectional area 3.0 * 10-6 m2 carries a current of 6.0 A and has a mobile charge density of 4.24 * 1028 carriers/m3, what is the average drift velocity of the mobile charge carriers? (charge value = 1.6 * 10-19 C)
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Choose question tag  In a certain material there is a current of 16 A flowing through a surface to the right, and there is an equal amount of positive and negative charge passing through the surface producing the current.How much negative charge passes through the surface?
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Choose question tag  When you flip a switch to turn on a light, the delay before the light turns on is determined by:
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Choose question tag  The size of the electric current in a electrical conductor is a function of which of the following?
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Choose question tag  The unit of electric current, the ampere, is equivalent to which of the following?
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Choose question tag  If the current in a wire is tripled, what effect does this have on the electron drift velocity in the wire?
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Choose question tag  When an electric current exists within a conducting wire, which of the following statements describes the condition of any accompanying electric field?
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Choose question tag  A metallic conductor has a resistivity of 18 * 10-6 Wm.What is the resistance of a piece that is 30 m long and has a uniform cross sectional area of 3.0 * 10-6 m2?
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Choose question tag  Wire A and Wire B are each carrying the same current.If the diameter of Wire A is twice that of Wire B, how does the drift velocity vdA in Wire A compare to that in in Wire B?
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