Math

posted by .

The resistance(r)of a wire varies directly as the length(L)of the wire and inversely as the square of the diameter(d). If the resistance is 9ohms in 50ft of wire that has a diameter of 0.05in, find the resistance in 50ft of a similar wire that has a diameter of 0.02in.





Resistance=constant*Length/diameter^2

Two ways you can work this:
1) In the equation, solve for the constant (you have resistance 9 ohms, Length 50, and diameter .05). Then use that constant in the equation to solve for the new conditions,

2) Notice the length is the same, however...


Resistance1=constant*Length1/diameter1^2

and

Resistance2=constant*Length2/diameter2^2

now dividing the second equation by the first, and noting that the length1 and length 2 are the same..

Resistance2/resistance1=(diameter2/diameter1)^2

or resistance2=resistance1(diameter2/diameter1)^2

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Physics

    Two wires with the same resistance have the same diameter but different lengths. If wire 1 has length L1 and wire 2 has length L2, how do L1 and L2 compare if wire 1 is made from copper and wire 2 is made from aluminum?
  2. Algebra II

    The resistance of a wire is inversely proportional to the square of its diameter. If an AWG (American wire gauge) size 12 conductor (0.0808-in. diameter) has a resistance of 14.8, what will be the resistance of an AWG size 10 conductor …
  3. Math

    If 750 m of 3.00-mm-diameter wire has a resistance of 27.6, what length of similar wire 5.00 mm in diameter will have the same resistance?
  4. algebra

    A three quarter inch wire has 12 ohms resistance. How much resistance has the same length of half-inch wire, if resistance varies inversely as the square of the diameter?
  5. Math

    The electrical resistance of a wire waves directly as its length & inversely as the square of its diameter if a wire 30m long and 0.75mm in diameter has a resistance of 25ohms , find the length of a wire of the same material whose …
  6. Algebra joint, inverse and direct variation

    Urgent! If t varies inversely as the cube of z and directly as the square of r, and t=4 when z=3 and r=6, find t when z=6 and r=9. T= k (square) r/(cubed) z 4=k (square) 6/ (cubed) 3 The electrical conductance of a wire varies directly …
  7. Algebra

    If t varies inversely as the cube of z and directly as the square of r, and t=4 when z=3 and r=6, find 9. T= k (square) r/(cubed) z 4=k (square) 6/ (cubed) 3 The electrical conductance of a wire varies directly as the square of its …
  8. Algebra

    If t varies inversely as the cube of z and directly as the square of r, and t=4 when z=3 and r=6, find 9. T= k (square) r/(cubed) z 4=k (square) 6/ (cubed) 3 The electrical conductance of a wire varies directly as the square of its …
  9. college algebra

    The electrical resistance of a wire of a given material varies as its length and inversely as the square of the diameter. if a wire 300 feet long and 0.05 inches in diameter has a resistance of 30 ohms, (a) find the resistance of a …
  10. Physics

    A nichrome wire of diameter 5mm and length 5m has resistivity of 10^-4 ohm meter. If wire is compressed to double it's diameter. Find the resistance in its new form. Also find the resistance of the wire originally ?

More Similar Questions