SOLUTION: The electrical resistance of a wire varies directly as its length and inversely as the Square of its diameter. If a wire with length 100cm and diameter 2mm has a resistance of 1.5

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Question 413955: The electrical resistance of a wire varies directly as its length and inversely as the Square of its diameter. If a wire with length 100cm and diameter 2mm has a resistance of 1.5 Ohms, find the resistance of a wire with length 300cm and diameter 3mm.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
The electrical resistance of a wire varies directly as its length and inversely as the Square of its diameter.
:
That would be:
r = L%2Fd%5E2
:
If a wire with length 100cm and diameter 2mm has a resistance of 1.5 Ohms,
let k = constant of variation
%28kL%29%2Fd%5E2 = r
%28100k%29%2F2%5E2 = 1.5
%28100k%29%2F4 = 1.5
25k = 1.5
k = 1.5%2F25
k = .06 is the constant of variation
:
find the resistance of a wire with length 300cm and diameter 3mm.
r = %28.06%2A300%29%2F3%5E2
r = 18%2F9
r = 2 ohms