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

When is thermal conductivity said to be constant?

Consider two rods of same length and different specific heats $(S_{1}, S_{2})$,conductivities $(K_{1}, K_{2})$ and area of cross-sections $(A_{1}, A_{2})$ and both having temperatures $T_{1}$ and $T_{2}$ at their ends. If the rate of loss of heat due to conduction is equal,then:

Two rectangular blocks $A$ and $B$ of different metals have the same length and the same area of cross-section. They are kept in such a way that their cross-sectional areas touch each other. The temperature at one end of $A$ is $100^{\circ}C$ and that of $B$ at the other end is $0^{\circ}C$. If the ratio of their thermal conductivities is $1 : 3$,then under steady state,the temperature of the junction in contact will be ........ $^{\circ}C$.

$A$ wall has two layers $A$ and $B$,each made of a different material. Both the layers have the same thickness. The thermal conductivity of the material of $A$ is twice that of $B$. Under thermal equilibrium,the temperature difference across the wall is $36\,^{\circ}C$. The temperature difference across the layer $A$ is ......... $^{\circ}C$

If $6000 \ J/s$ of heat flows through a conductor of length $1 \ m$ and cross-sectional area $0.75 \ m^2$,then the temperature difference between its ends is ...... $^\circ C$. $[K = 200 \ J/(m \cdot K)]$