Question

From what minimum height, a block of ice has to be dropped in order that it may melt completely on hitting the ground :

• A. $mgh$
• B. $\frac{mgh}{l}$
• C. $\frac{l}{g}$
• D. $\frac{h}{lg}$

Answer 1

The correct option is C $\frac{l}{g}$

Let the mass of the ice be m then
$m\times g\times h=m\times l$ , where l is the latent heat of melting.
$h=\frac{l}{g}$