A uniform rod is suspended horizontally from its mid-point. A piece of metal whose weight is w is suspended at a distance l from the mid point. Another weight W1 is suspended on the other side at a distance l1 from the mid-point to bring the rod to a horizontal position. When w is completely immersed in water, w1 needs to be kept at a distance l2 from the mid-point to get the rod back into horizontal position. The specific gravity of the metal piece is