Suppose you wish to fabricate a uniform wire from a mass m of a metal with density rhom and resistivity rho. if the wire is to have a resistance of r and all the metal is to be used, what must be the length and the diameter of this wire? (use any variable or symbol stated above as necessary.

Explanation:

Resistivity and resistance are proportional and depends of the length and the cross-sectional area of the wire:

furthermore, the density is the mass divided by the volume, and the volume can be written as the area multiplyed by the length:

Now you have tw equations and two variables, so you can solve for each of them.

first, solve for A in both equations and replace them:

now replace this into any of the previous equiations:

If you assume the wire has circular cross-sectional area, then the area is:

solving for d:

replacing A and simplifying:

b mirrors submit a iisner? e. for which optical devices does d sometimes have a positive value? o a a and b o b. a and c o c. b and d 0 d. b and cb

causes

fossil fuels burn

cities become more industrialized

human population grows worldwide