Question

PLEASE HELP!! PHYSICS QUESTION-DOES ANYONE KNOW HOW TO DO THIS WITH THE WORKING OUT?!?

Taking the resistivity of platinoid as 3.3 x 10-7 m, find the resistance of 7.0 m of platinoid wire of average diameter 0.14 cm.

Answer 1

`1.5 \Omega`

Step-by-step explanation:

The resistance of a piece of wire is given by

`R=(\rho L)/(A)`

where

`\rho` is the resistivity of the material

L is the length of the wire

A is the cross-sectional area

In this problem, we have

`\rho = 3.3\cdot 10^(7) m`

L = 7.0 m

The diameter of the wire is 0.14 cm, so the radius is 0.07 cm, therefore the cross sectional area is

`A=\pi r^2 = \pi (0.07)^2=0.0154 cm^2 = 0.0154\cdot 10^(-4) m^2`

Therefore, the resistance is

`R=((3.3\cdot 10^(-7))(7.0))/((0.0154\cdot 10^(-4)))=1.5 \Omega`