I need MAJOR HELP with this math question too!!!..???

Question

The electrical conductance of a wire varies directly as the square of its diameter and inversely s its length. The conductance of a wire 20m long and 3mm in diameter is 0.54 mho. If a wire of the same material has length 50mm and diameter 5mm, what is its conductance?

please show me your work because I have to write this down....thanks..^_^

Answer 1

let c1 and c2 be the two conductances........
d1 nd d2 thier dia
and l1 and l2 their lengths

then c1/c2= d1^2/d2^2* (l2/l1)

0.54/c2= 3^2/5^2*(50/(20*1000))

c2=600 mho

i think the length is 50 m not 50 mm..
then the ans is 0.6 mho

Answer 2

Let conductance be c1
C1 : D^2 / L
C2: d^2 / l

c1/c2 = (D^2 / L) / (d^2 / l)

0.54/c2 = (3*3 / 20) / (5 * 5/0.05) (50mm = 0.05 m)

0.54 /c2 = 9/20 * 0.05/25
0.54/c2 = (0.45) / 500
c2 = (0.54 * 500) / 0.45
c2 = 600 mho

Answer 3

0.54=k*d^2/l so 0.54=k*9/20 and k= 20*0.54/9=1.2
so
x=1.2*25/0.05 = 600 mho
Are you sure that the length is 50mm.
In any case to fit the formula you have to express length in meter