An ice block at `0^(@)C` and of mass m is dropped from height `'h'` such that the loss in gravitational potential energy of block is exactly equal to the heat required to just completely melt the ice. Taking latent heat of fusion of ice `= 80 cal//gm`, acceleration due to gravity `= 10 m//s^(2)` and mechanical equivalent of heat `= 4.2 J//Cal`. the value of `'h'` is