Question

A rectangular ice box of total surface area of 1000 cm$^2$ initially contains 1.5 kg of ice at 0 $^\circ$C. If the thickness of the walls of the box is 2 mm and the temperature outside the box is 42 $^\circ$C, then the mass of the ice remaining in the box after 160 minutes is (Thermal conductivity of the material of the box = $10^{-2}$ Wm$^{-1}$K$^{-1}$ and latent heat of the fusion of ice = $336\times10^3$ Jkg$^{-1}$)

• A. 0.6 kg
• B. 0.9 kg
• C. 0.8 kg
• D. 0.7 kg

Hint:

This is a two-part problem. First, use the heat conduction formula ($\frac{dQ}{dt} = \frac{kA\Delta T}{d}$) to find the rate of heat flow. Second, use the latent heat formula ($Q = mL_f$) to relate the total heat transferred to the mass of substance that undergoes a phase change.

Answer 1

The Correct Option is B