1. An unknown alloy is subjected to an electric field of 25 V/m, and has a current density of 1.45X 10 9 A/m2 .What is the metal's resistivity?2. A copper-nickel alloy called constantan has a resistance of 8.55 X 10 4 m2 at 20.0 °C. What is its resistanceif it is subjected to a temperature of 1500.0 °C? Assume that Equation for resistance is applicable at veryhigh temperature change.3. The temperature dependence of metal makes it possible for it to be used as a resistance thermometer, whichinvolves platinum. Platinum has a resistance of 50.0 N at 20.0 °C. When it is immersed in a melting metalindium, its resistance increases to 7.68 X 10 4 mQ. What is the melting point of indium in Kelvin?

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Answered: 1. An unknown alloy is subjected to an…

1. An unknown alloy is subjected to an electric field of 25 V/m, and has a current density of 1.45 × 10 9 A/m2 . What is the metal's resistivity?

College Physics

11th Edition

ISBN:9781305952300

Author:Raymond A. Serway, Chris Vuille

Publisher:Raymond A. Serway, Chris Vuille

Chapter1: Units, Trigonometry. And Vectors

Section: Chapter Questions

Problem 1CQ: Estimate the order of magnitude of the length, in meters, of each of the following; (a) a mouse, (b)...

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3. Look up tabulated conductivities (or resistivities) of copper, silver, and aluminum at 20 °C and calculate the resistance of a copper wire that is 2 meters long with a1 mm diameter. Repeat your calculation for silver, and for aluminum. The density of free electrons is 8.5x1028 particles/m3 for copper, 5.86x 102 m-3 for silver, and 18.1x1028 m-3 for aluminum. For a potential difference of 5 volts, how do the electron drift velocities in each of the three wires compare with one another?
2.A current-carrying gold wire has a diameter 0.84 mm. The electric field in the wire is 0.49 V/m. What are (a) the current carried by the wire (b) the potential difference between two points in the wire 6.4 m apart; (c) the resistance of a 6.4-m length of this wire?
4. A current of 280 mA flows in a wire. The charge carriers are electrons. The cross-sectional area of the wire is 0.21 mm2. If there are 6.4 x 1028 electrons per cubic meter, then find the drift speed of the electrons.
4. An aluminium wire with a diameter of 0.100 mm has a uniform electric field of 0.200 V/m imposed along its entire length. The temperature of the wire is 50.0°C. Assume one free electron per atom (T=20°C). (a) Use the information in Table A2.1 to determine the resistivity of aluminium at this temperature. (b) What is the current density in the wire? (c) What is the total current in the wire? (d) What is the drift speed of the conduction electrons? (e) What potential difference must exist between the ends of a 2.00-m length of the wire to produce the stated electric field? Table A2.1. Resistivities and Temperature Coefficients of Resistivity for Various Materials Temperature Coefficient a [(°C)-¹] Material Silver Copper Gold Aluminum Tungsten Iron Platinum Lead Nichromec Carbon Germanium Silicond Glass Hard rubber Sulfur Quartz (fused) Resistivitya (m) 1.59 × 10-8 1.7 X 10-8 2.44 X 10-8 2.82 × 10- -8 5.6 × 10-8 10 × 10-8 11 X 10-8 22 × 10-8 1.00 × 10-6 3.5 × 10- -5 0.46 2.3 × 10³ 10¹⁰…
C. Answer the following question/s: 1. Discuss what electric current is with respect to how you understand drift velocity of moving electric charges. 2. In what ways are electron flow and electric current the same? In what ways are these terms different? 3. How is drift velocity dependent on current density? D. Solve the following: 1. Calculate the current produced by a charge of 4.15 x 10-17 C that flows for 10 s. 2. Identify how many electrons flow through a lightbulb for each second if the current through the bulb is 0.75 A. 3. A steady current of 0.75 A flows through a conductor. Determine the number of charges that passes through the wire in 3 min. 4. Determine the number of electrons that pass per second through a section of wire carrying a current of 0.8 A.
1. Nichrome is a metal alloy that has a resistivity of 108 X 10Q m. a) What is the resistance of a nichrome wire of length 5.00 m and diameter 1.32 mm? b) If the wire in part (a) above is connected to a cell of emf 1.55 volts and it is found that a current of 365 mA flows, what is the Internal resistance of the cell?
20. A current of 3.3 A is going through a copper wire (n=8.4x1028 m-³) with a diameter of 4.5 mm. What is the electron drift speed in the wire? [1.54x10-5 m/s]
2. A copper wire of diameter 0.86 mm carries a constant current of 0.18A to a 40 W bulb. The free-electron density in the wire is 6.3 x 1028 per cubic meter. Find (a) the current density and (b) the drift speed.
17. A steel trolley-car rail has a cross-sectional area of 56 cm². What is the resistance of 11 km of rail? The resistivity of the steel is 3.0 X 10-" N•m.
51&page=1 What is the resistance (in units of Q) of a wire made of a material with a resistivity of 3.2 x 10-8 Q. m, if its length is 10.7 m and its diameter is 0.50 mm? Select one: O A. 6.02 OR. 0.67 OC.0.44 OD. 3.88 OE. 1.74 Next page 601 AM A O G d ENG 4/15/2021
A conductor has a cross-sectional area of 2.3x 10P m and the number of free electrons per unit volume is 8.5x 1028 electron/m³. When the current is 6.1 A, find the drift speed (in mm/s) of the electrons. Use the charge of the electron to be 1.6x1019 C. Select one: OA 0.26 OB. 25.60 OC.0.13 OD. 19.50 OE 0.20
A thermometer made of Platinum has a resistance of 50 2 at 20 C, what is the measured temperature (in units of C) when its resistance is 86.8 2. Assume the temperature coefficient of resistivity to be a= 3.92×10-3 c-1 Select one: O A. 134.15 O B. 442.85 O C. 207.75 D. 677.96 O E. 187.75