Question

The two opposite faces of a cubical piece of iron are at $100{}^{\circ }C$ and $0{}^{\circ }C$ in ice. If the area of surface is 4 $c{m}^2,$ then the mass of ice melted in 10 min will be (Thermal conductivity of iron = 0.2 CGS units)

• A. 5 g
• B. 30 g
• C. 50 g
• D. 300 g

Answer 1

Answer: (D)

$Q=mL=KA\frac{({\theta }_1-{\theta }_2)}{l}t$ $\Rightarrow$ $m=\frac{1}{L}\times KA\frac{({\theta }_1-{\theta }_2)}{l}\times t$ $=\frac{1}{80}\times 0.2\times 4\times \frac{(100-0)}{\sqrt{4}}\times 10\times 60$ $(\because l^2=4\Rightarrow l=\sqrt{4})$ $=\frac{0.2\times 4\times 100\times 600}{80\times 2}=300g$