A wire of resistivity p is pulled to double its length. What will be its new resistivity?

Explanation

`R=(rhoL)/A`
When L becomes 2L, A becomes A/2
`R=(rho2L)/(A/2)=(4rhoL)/A=4R`
New resistance becomes 4 times the original one. But, resistivity remains the same as it is the property of the substance and does not change with length or area.