A steel wire of length 4.7 m and cross-sectional area `3.0xx10^(-5)m^(-2)` stretched by the same amount as a copper wire of length 3.5 m and cross-sectional area of `4.0xx10^(-5)m^(2)`.

Explanation

Given, for steel wire, `a_(1)=3.0xx10^(-5)m^(2),l_(1)=4.7m,Deltal_(1)=Deltal,F_(1)=F`
For copper wire, `a_(2)=4.0xx10^(-5)m^(2),l_(2)=3.5m`
`Deltal_(2)=Deltal,F_(2)=F`
Let `y_(1),y_(2)` be the young modulus of steel wire and copper wire respectively.
`therefore y_(1)=(F_(1))/(a_(1))xx(l_(1))/(Delta_(2))=(F)/(3.0xx10^(-5))xx(4.7)/(Deltal)` . . (i)
and `y_(2)=(F_(2)xxl_(2))/(a_(2)xxDeltal_(2))=(Fxx3.2)/(4xx10^(-5)xxDeltal)` . . . (ii)
`(y_(1))/(y_(2))=(4.7xx4xx10^(-5))/(3.5xx3.0xx10^(-5))=1.8`
Here `y_(1):y_(2)=1.8:1`.