Copper of fixed volume `V` is drawn into wire of length l. When this wire is subjected to a constant force F, the extension produced in the wire is `trianglel`. Which of the following graphs is a straight line?

Options

A. `Delta l` versus `1//l`
B. `Delta l` versus `l^(2)`
C. `Delta l` versus `1//l^(2)`
D. `Delta l` versus `l`

Answer

B

Explanation

Volume `V=Al` or `A=V//l`
`Y=(Fl)/(A Delta l)=(F l)/((V/l)Delta l)=(Fl^(2))/(V Delta l)`
`Delta l=(F l^(2))/(Vy)` , So `Delta l prop l^(2)`