Physics; essay

1)The typical wire we might use could be made of Aluminum (resistivity 2.75 x 10^-8 ohm m. The length of the wire is 2.00m. Calculate the diameter we would need to have a resistance of 4.00 x 10^-3 ohm. How does this diameter compare with typical diameters used for copper wires? This may give you a hint as to why we can neglect the resistance of wires for circuits that have resistances in the range of one ohm and up. Do a similar calculation for wires made of tungsten ( resistivity = 5.25 x 10^-8 ohm m and copper (resistivity 1.69 x 10^-8 ohm m).

2)Write a brief essay on why resistivity is an important property to measure for solid materials. Include a discussion of what the temperature dependence of resistivity is at low temperatures (near absolute zero). Historically, the examination of resistance at low temperature led to the discovery of superconductors!

Sample Solution