Surface of the lake is at $2^{\circ} C$. The temperature of the bottom of the lake is ....... $^{\circ} C$

Three rods made of the same material and having the same cross section have been joined as shown in the figure. Each rod is of the same length. The left and right ends are kept at ${0^o}C$ and ${90^o}C$ respectively. The temperature of the junction of the three rods will be ...... $^oC$

The rate of heat flow through the cross-section of the rod shown in figure is ($T_2 > T_1$ and thermal conductivity of the material of the rod is $K$)

Ice formed over lakes has

If the radius and length of a copper rod are both doubled, the rate of flow of heat along the rod increases ....... times

One end of a copper rod of length $1.0\;m$ and area of cross-section ${10^{ - 3}}$ is immersed in boiling water and the other end in ice. If the coefficient of thermal conductivity of copper is $92\;cal/m{\rm{ - }}s{{\rm{ - }}^o}C$ and the latent heat of ice is $8 \times {10^4}cal/kg$, then the amount of ice which will melt in one minute is