Question

There is ice formation in a tank of water of thickness 10 cm. How much time it will take to have a layer of 0.1 cm below it ? The outer temperature is – 5^0C, the thermal conductivity of ice K = 0.005 cal/cm-sec^0C, the latent heat of ice is 80 cal/gm and the density of ice is 0.91 gm/cc

• A. 46.39 minutes
• B. 47.63 minutes
• C. 48.77 minutes
• D. 49.31 minutes

Answer 1

Answer: (C)

48.77 minutes

Answer 2

$t = \frac{\rho l}{2k\theta}\left( y_{2}^{2} - y_{1}^{2} \right) = \frac{0.91 \times 80}{2 \times 0.005 \times 5}\lbrack(10.1)^{2} - (10)^{2}\rbrack = 2926sec = 48.77min.$