A piece of ice falls from a height $h$ so that it melts completely. Only one-quarter of the heat produced is absorbed by the ice and all energy of ice gets converted into heat during its fall. The value of $h$ is:
(Latent heat of ice is $3.4\times {10}^5{\text{J kg}}^{-1}$ and $g=10{\text{N kg}}^{-1}$)