Two vessels identical in geometry but made of different materials contain equal quantities of ice. The ice melts in 20 min and 30 min, respectively. Find the ratio of vessel thermal conductivities k₁/k₂.
Physics · Mixed Chapter
JEE Main Practice

Question

Two vessels identical in geometry but made of different materials contain equal quantities of ice. The ice melts in 20 min and 30 min, respectively. Find the ratio of vessel thermal conductivities k₁/k₂.

Physics · Mixed Chapter

G1 Physics · Accepted Answer

Step 1: Under the same temperature difference and geometry, heat-flow rate obeys Q̇ ∝ k. Step 2: To melt the same amount of ice, total heat required is fixed; melting time t=Q/Q̇∝1/k. Step 3: Therefore k₁/k₂=t₂/t₁=30/20=1.5. Step 4: Original PDF key says 1.05; this contradicts the conduction model and data.