The length of the resistance wire is increased by `10%`. What is the corresponding change in the resistance of wire?

Options

A. 0.1
B. 0.25
C. 0.21
D. 0.09

Answer

C

Explanation

If volume and density remains same, then resistance of wire, `R prop l^(2)`
Where, l is the length of the wire.
`therefore " " R'(l+(10)/(100)l)^(2)=((11)/(10))^(2) R`
Hence, `(R'-R)/(R )=(21)/(100)=21%`
Therefore, change in resistance of wire = 21 %.