A steel wire is suspended vertically from a rigid support. When loaded with a weight in air, it extends by la and when the weight is immersed completely in water, the extension is reduced to lw. Then the relatively density of material of the weight is

Let V be volume of the load, and let its relative density be ρ thenY=FLAla=VρgLAla.......(1)when the load is immersed in liquid, the net weight = weight - upthrust∴Y=F'LAlw=(Vρg-V×1×g)LAlw.........(2) Equating (1) and (2), we get ρla=ρ-llw  which gives ρ=lala-lw