Question

A glass container cracks when very hot tea is poured into it a probable reason for this is the ________.

• A. low specific heat of gas
• B. low thermal conductivity of glass
• C. high thermal conductivity of glass
• D. None of the above

Answer 1

The correct option is B low thermal conductivity of glass

Rate of heat flow, $\frac{Q}{t}=\frac{kA\Delta T}{l}$, where $k$ is thermal conductivity, $A$ is the cross-sectional area of material, $l$ is the length of the material.

As glass has lower thermal conductivity, it is poor conductor of heat, and doesn't conduct the heat from one side to the other. So hotter side expands while cooler side doesn't, which generates the shear stress and the glass breaks.