A well insulated box is packed with ice at 0°C and kept in a room at a temperature of 30°C. The lid of the box is made of a cardboard sheet of thickness 4 mm and area 100 "cm"^(2). If the ice melts at the rate of 0.045 kg per hour, calculate the thermal conductivity of cardboard assuming that heat can enter the box only through the lid. [L.H. of fusion of ice = 336 "KJ/kg" ]

A well insulated box is packed with ice at 0°C and kept in a room at

1.	A well insulated box is packed with ice at 0°C and kept in a room at a temperature of 30°C. The lid of the box is made of a cardboard sheet of thickness 4 mm and area 100 "cm"^(2). If the ice melts at the rate of 0.045 kg per hour, calculate the thermal conductivity of cardboard assuming that heat can enter the box only through the lid. [L.H. of fusion of ice = 336 "KJ/kg" ]
Answer» ANSWER :`0.056 "WM"^(-1) "K"^(-1)`