A hollow glass sphere with external and internal radii of and

PHYSICS · Subjective · CBSE · Physics · Thermal Properties of Matter · Thermal Properties of Matter

Problem

A hollow glass sphere with external and internal radii of

11\text{ cm}

and

9\text{ cm}

, respectively, is completely filled with ice at

0^\circ\text{C}

and placed in a bath of boiling water. How long will it take for the ice to melt completely? Given: density of ice

=0.9\text{ g cm}^{-3}

, latent heat of fusion of ice

=80\text{ cal g}^{-1}

, and thermal conductivity of glass

=0.002\text{ cal cm}^{-1}\text{s}^{-1}\,{}^\circ\text{C}^{-1}