The graph shows the extension of a wire of length 1m suspended from the top of a roof at one end and with a load W connected to the other end. If the cross sectional area of the wire is `1mm^(2)`, then the young's modulus of the material of the wire is
(a). `2xx10^(11)Nm^(-2)`
(b). `2xx10^(10)Nm^(-2)`
(c). `(1)/(2)xx10^(11)Nm^(-2)`
(d). none of these

Explanation

`Y=(F//A)/(Deltal//l)=(Wl)/(A Deltal)impliesW/(Deltal)=(YA)/l=` slope
`impliesY=l/A` (slope) `=1/10((40-20)/((2-1)xx10^(-3)))`
`=2xx10^(10)Nm^(-2)`