Solve this:
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 :
$[ Laten heat of ice is 3.4\times {10}^5 J/Kg and g=10 N/Kg]$
(1) 34 km           (2) 544 km            (3) 136 km            (4) 68 km