Problema Solution

In the electric current flow, it is found that the resistance (measured in the units OHMs) offered by a fixed length of wire of a given material varies inversely as the square of the diameter of the wire. if a wire 0.01 in. in diameter has a resistance of 0.431 ohm what is the resistance of a wire of the same length and material with a diameter of 0.0323.

Answer provided by our tutors

Resistance X Diameters square = Constant

Let 

R = resistance

d = diameter

C = constant

Rd^2 = C

For d = 0.1 we have R = 0.431 ohm:

0.431*0.1^2 = C 

For d = 0.0323 we have:

R*0.0323^2 = 0.431*0.1^2

R = 4.131 ohm

The resistance of a wire of the same length and material with a diameter of 0.0323 in is 4.131 ohm.