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

Answer

D

Explanation

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