The Poisson's ratio of a material is 0.4. If a force is applied to a wire of this material, there is a decrease of cross-sectional area by 2%. The percentage increase in its length is

Options

A. 0.03
B. 0.025
C. 0.01
D. 0.005

Answer

B

Explanation

Poisions's Ratio, `micro = (Deltar//r)/(Deltal//l)`
`(Deltal)/l = (Deltar)/r xx 1/micro`
`= (Deltarr)/r xx 1/0.4`
`Deltal = (Deltar)/(0.4r) xx100`
`2/2 xx 12/0.4`
`2.5%`