on a cold winter day, the atmospheric temp.is t which isbelow 0degree celcius.acylindrical drum of height h made of bad conductoris completely filled with water at0 degree celcius&is kept outside without any lid.calculate the tim e taken by the whole of water 2 freezethermal conductuivity of ice is k &latent heat of fusion is l.neglect the expansion of water on freezing. my approach q/t=ka(t)/h wher t is temp difference qneeded 2 freeze wateris=ml=d*vol. of cylinder*l where l islatent heat of fusion d=density of water time=qh/ka t my answer came 2 b dlh(square)/kt where as the answer in book is mine answer/2 what's the fallacy in my approach

on a cold winter day, the atmospheric

temp.is t which isbelow 0degree

celcius.acylindrical drum of height h

made of bad conductoris completely

filled with water  at0 degree celcius&is

kept outside without any lid.calculate

the tim e taken by the whole of water 2

freezethermal conductuivity of ice is k

&latent heat of  fusion is l.neglect the

expansion of water on freezing.

my approach
q/t=ka(t)/h wher t is temp difference
qneeded 2 freeze wateris=ml=d*vol. of

cylinder*l where l islatent heat of

fusion  d=density of water
 

time=qh/ka t
my answer came 2 b dlh(square)/kt where as the answer in book is mine answer/2
what's the fallacy in my approach