A wire of `10 Omega ` resistance is stretched to thrice of its original length . What will be its new resistance and resistivity ?

Explanation

We know that , resistance ,`R prop l/A`
`:. " "(R_(1))/(R_(2)) =(l_(1))/(l_(2)),(A_(2))/(A_(1))=(l/(3l)).(A/(3A))`
`:. " " (10)/(R_(2)) =1/9`
`rArr " "R_(2) = 90 Omega `
Since , the resistivity is the property of the body it will not change .