Posted by **Amber** on Friday, September 22, 2006 at 3:04am.

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

## Answer this Question

## Related Questions

- algebra - A three quarter inch wire has 12 ohms resistance. How much resistance ...
- Algebra II - The resistance of a wire is inversely proportional to the square of...
- Physics - Two wires with the same resistance have the same diameter but ...
- Math - If 750 m of 3.00-mm-diameter wire has a resistance of 27.6, what length ...
- Math - If 750 m of 3.00-mm-diameter wire has a resistance of 27.6, what length ...
- Algebra II - If 750 m of 3.00-mm-diameter wire has a resistance of 27.6, what ...
- Algebra II - If 750 m of 3.00-mm-diameter wire has a resistance of 27.6, what ...
- Alegra II - If 750 m of 3.00-mm-diameter wire has a resistance of 27.6, what ...
- physics - Suppose that you wish to fabricate a uniform wire out of 0.900 g of ...
- physics - the resistance of copper wire of length 1m is 0.1 ohm the diameter of ...

More Related Questions