Figure shows a cubical block of side 10 cm and relative density 1.5 suspended by a wire of cross-sectional area ${10}^{-6}{\mathrm{m}}^2$ . The breaking stress of the wire is $7\times {10}^6\mathrm{N}/{\mathrm{m}}^2$ . The block is placed in a beaker of base area $200{\mathrm{cm}}^2$ and initially i.e. at $\mathrm{t}=0$, the top surface of water and the block coincide. There is a pump at the bottom corner which ejects $2{\mathrm{cm}}^3$ of water per sec. Find the time (in sec) at which the wire will break.