An object weighs Wa in air. When immersed fully in water it weighs Ww. If on immersing in a liquid, the object weighs Wl, the relative density of the liquid is
1
\(W_a\over W_a-W_w\)
2
\(W_a\over W_a-W_l\)
3
\(W_l\over W_w\)
4
\(W_a-W_l\over W_a-W_w\)