Question

2kg of Ice block should be dropped from ‘x km’ height to melt completely. The 8 kg of ice block should be dropped from height

• A. 4x km
• B. x km
• C. 2x km
• D. 3x

Answer 1

The correct option is B x km

Work done by gravity is being converted into heat that is melting the ice ,

$\therefore$ we have $m\times g\times h=m\times L$
$\Rightarrow h=L/g$
Where $L$ is latent heat of fusion. From here we can see that height is independent of mass.

So, 8 kg if ice block should be dropped from height $x$.