- #1
Marbles
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Sorry everyone, I forgot to post my efforts in solving the problem, so here I go again:
The question says: Suppose you wish to fabricate a uniform wire out of 1.00 g of copper. If the wire is to have a resistance of R=0.500 Ohm, and a density of d=8920 kg/m3, and if all the copper is to be used, what will be the:
a)length of the wire? >>ans. is 1.82 m
b) diameter of the wire? >>ans. is 0.28 mm
The equation is: R=p(rho)*l(length)/A(cross sectional area)
I found the area only, I'm lost!
But at least, based on the area, my diameter is supposed to be correct, but it wasn't!
I got 0.001>>lol
Anyways, I will show you what I did to find the area and the diameter:
First I found the volume of the wire: v=m(mass)/d(density)=0.001 kg/(8920 kg/m3)
and I got 1.12e(-7) m3
Then I found height, guess how!
R=p*l/A right?? ok, I canceled the length on top (numerator) with the length in the area equation: L*h and I was left with R=p/h, which means h=p/R=1.72e(-80) (rho or resistivity of copper, got it from our textbook)/0.5= 3.44e(-8) m
Now I substituted both values in the formula: A=v/h=1.12e(-7)/3.44e(-8)=3.25 m2
Now I used it to find the diameter: d=A/pi=3.25/3.14(pi)= 0.001 mm
I know that there are several mistakes, so I'd like you all to help me improve my solution and also help me find the length. I'd really appreciate that!
The question says: Suppose you wish to fabricate a uniform wire out of 1.00 g of copper. If the wire is to have a resistance of R=0.500 Ohm, and a density of d=8920 kg/m3, and if all the copper is to be used, what will be the:
a)length of the wire? >>ans. is 1.82 m
b) diameter of the wire? >>ans. is 0.28 mm
The equation is: R=p(rho)*l(length)/A(cross sectional area)
I found the area only, I'm lost!
But at least, based on the area, my diameter is supposed to be correct, but it wasn't!
I got 0.001>>lol
Anyways, I will show you what I did to find the area and the diameter:
First I found the volume of the wire: v=m(mass)/d(density)=0.001 kg/(8920 kg/m3)
and I got 1.12e(-7) m3
Then I found height, guess how!
R=p*l/A right?? ok, I canceled the length on top (numerator) with the length in the area equation: L*h and I was left with R=p/h, which means h=p/R=1.72e(-80) (rho or resistivity of copper, got it from our textbook)/0.5= 3.44e(-8) m
Now I substituted both values in the formula: A=v/h=1.12e(-7)/3.44e(-8)=3.25 m2
Now I used it to find the diameter: d=A/pi=3.25/3.14(pi)= 0.001 mm
I know that there are several mistakes, so I'd like you all to help me improve my solution and also help me find the length. I'd really appreciate that!