A mild steel wire of length 1 m and cross-sectional area 0.5 x {{10}^{-2}} c${{m}^{2}} is stretched, well within its elastic limit, horizontally between two pillars. A mass of 100 g is suspended from the mid-point of the wire. Calculate the depression at the mid-point. If Young's modulus for steel = 2x {{10}^{11}}$ Pa.