The graph below shows how the force applied to a metal wire is related to the extension of the wire. The wire has an unstretched length of `2.30m` and an area of cross section of `3.90 xx 10^-7m^2`. Determine the Young's modulus `Y` of the material.

A steel wire of length 4.7m and cross sectional area 2xx10^-5m^2 stretches by the same amount as a copper wire of length 3.5m and cross sectional area of 4xx10^-5m^2 under a given load. What is the ratio of the Young's modulus of steel to that of copper?