Question

A thermocole cubical icebox of side 30 cm has a thickness of 5.0 cm if 4.0 kg of ice are put ini the box, estimate the amount of ice remaining after 6 h. The outside temperature is `45^@C` and coefficient of thermal conductivity of thermocole`=0.01 J//kg`.

Answer 1

Correct Answer - `3.739` kg
`Q = KA((theta_(1) - theta_(2)) t)/(l) = mL`
`implies m xx 335 xx 10^(3)`
=`0.01 xx (0.54 xx 45 xx6 xx 60 xx 60)/(5 xx 10^(-2))`
`implies m = 0.261`kg
Therefore mass of ice left in the box after `6` hours = `( 4 - 0.261) kg = 3.739`kg