There are two idential springs of copper and steel. They are stretched by equal forces. For which spring more work will have to be done?

Explanation

We know that Young's modulus of steel is more than that of copper.
as , `Y=F/A xx l/(Delta l) or Delta l = (Fl)/(AY) so Delta l prop 1/Y`
`(Delta l_(cu))/(Delta l_(steel)) = (Y_(steel))/(Y_(cu)) gt 1 or Delta l_(cu) gt Delta l_(steel)`
Work done, `W= 1/2 F Delta l or W prop Delta l`
` [ :' ` F os constant]
so more work will have to be done on copper wire than that on steel wire.