Question

A' thermacole' icebox is a cheap and efficient method for storing small quantities of cooked food in summer in particular. A cubical icebox of side 30 cm has a thickness of 5.0 cm. If 4.0 kg of ice is put in the  box, estimate the amount of ice remaining after 6 h. The outside temperature is 45°C, and coefficient of thermal conductivity of thermacole is 0.01 Js^-1 m^-1 °C^-1,[Heat of fusion of water = 335 X 10³ J Kg^-1].

Answer 1

Side of cubical icebox,

l = 30 cm = 0.3 m

∴ Total Surface area,

∴ The amount of heat exchanged,

∴ Mass of ice left in the icebox after 6 hours,

= 4.0 - 0.313 = 3. 687 kg.