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

Options

A. 8m
B. 8 km
C. 33.6 m
D. 33.6 km

Answer

D

Explanation

From given statement
`mgh=mL ` or `gh=L`
or `10xxh=(80xx4.2)/(10^(-3))` or `h=33.6xx10^(3)` meter =33.6 km