What Metal Is the Wire Made Of Based on Its Resistivity?

AI Thread Summary
The discussion revolves around determining the metal of a wire based on its resistivity, given its dimensions and electrical properties. The wire is 50.0 m long with a diameter of 2.00 mm, connected to a 9.11 V source, resulting in a current of 23.45 A. The resistance was calculated to be 0.388 ohms, but initial area calculations were incorrect due to using diameter instead of radius. After correcting the area calculation to use the radius, the resistivity was recalculated but still did not match any provided options for gold, silver, copper, or iron. The key issue highlighted is the importance of accurately calculating the cross-sectional area of the wire.
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Homework Statement



A wire, 50.0 m long and 2.00 mm in diameter is connected to a source with a potential difference of 9.11 V, and the current is found to be 23.45 A. Assume a temperature of 20°C and using Table 17.1, identify the metal out of which the wire is made of.

Homework Equations



R=p(l/A)

where R is the resistance p is the coefficient of resistivity, l is the length and A is the area

The Attempt at a Solution



ok since we are solving for p first i found R by the equation V=IR and found R to be .388
next i found the area using the surface area of a cylinder and found that to be .628
next i divided length by .628 and found that to be 79.618
so then i divided .388/79.618 and got 4.8*10^-3
thats the right magnitude but it does match any of my options coefficients.

the problem let's me choose whether the metal is gold, silver, copper, or iron.
 
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goWlfpack said:

Homework Statement



A wire, 50.0 m long and 2.00 mm in diameter is connected to a source with a potential difference of 9.11 V, and the current is found to be 23.45 A. Assume a temperature of 20°C and using Table 17.1, identify the metal out of which the wire is made of.

Homework Equations



R=p(l/A)

where R is the resistance p is the coefficient of resistivity, l is the length and A is the area

The Attempt at a Solution



ok since we are solving for p first i found R by the equation V=IR and found R to be .388
next i found the area using the surface area of a cylinder and found that to be .628

wrong area. you want the cross-sectional area of the wire

next i divided length by .628 and found that to be 79.618
so then i divided .388/79.618 and got 4.8*10^-3
thats the right magnitude but it does match any of my options coefficients.

the problem let's me choose whether the metal is gold, silver, copper, or iron.
 
ugh ok i got the area by .002*.002*3.14 = .00001256
then i divided 50/.00001256 and got 3980891.72
so then i divided my R .388 by 3980891.72 an got 9.74e-8
not right...
 
please help i really don't understand why this is still wrong...
 
you still have the wrong number for the area. The *diameter* is 0.002. The *radius* is 0.001.
You used Area=diameter*diameter*Pi, which is wrong.

Area=radius*radius*Pi
 
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