Question

There are two metallic wires of the same thickness Made up of iron and silver if the length of the iron wire is 12cm What should be the length of the Silver wire which is equal to the resistance of the iron wire

Answer 1

Answer:

1.96 cms

Explanation:

The resistance of a certain conductor or a wire depends upon the cross sectional area that also known as thickness of the wire, resistivity which is denoted by Greek letter rho(p) that depends on the build of the conductor that is the material of the wire that gives a constant value of resistivity to that particular materials. Lastly it depends on the length of the material.

Hence the relationship can be shown as

R=pl/a

As the thickness of the iron and silver wire is same and so is the resistance, we will have the ratio as

p1l1=p2l2

keeping resistivity and length on either sides

p1/p2= l1/l2

Given l1, length of iron is 12cms and value of resistivity of iron and silver is 9.71*10^-8

and 1.59 × 10^−8

Hence after putting all the values

l2= 1.96 cms