Identical springs of steel and copper are equally stretched. On which more work will have to be done?

Explanation

Work done in stretching a spring, `W=1/2 F xx Deltal`
where `Delta l` increases in length due to applying force,
` therefore W prop Delta l[ because (1)/(2) , F` constant]
`therefore W prop (l)/(Y) [ because Delta l = (Fl )/(AY), F, l, A` are constant]
`therefore (W_("steel "))/(W_("copper")) = (Y _("copper "))/( Y _(steel"))`
but ` Y _("steel " ) lt W _("copper")`
`therefore ` Hence, more work will be done in case in spring made of copper.