$A$ wall is made of equally thick layers $P$ and $Q$ of different materials. The thermal conductivity of $Q$ is half of that of $P$. In the steady state,if the temperature difference across the wall is $24^{\circ} C$,then the temperature difference across the layer $P$ is ............... . (in $^{\circ} C$)

In a steady state,the temperatures at the ends $A$ and $B$ of a $20\,cm$ long rod $AB$ are $100\,^{\circ}C$ and $0\,^{\circ}C$ respectively. The temperature of a point $C$ at a distance of $9\,cm$ from $A$ is....... $^{\circ}C$

$A$ cylindrical steel rod of length $0.10 \,m$ and thermal conductivity $50 \,Wm^{-1}K^{-1}$ is welded end to end to a copper rod of thermal conductivity $400 \,Wm^{-1}K^{-1}$ and of the same area of cross-section but $0.20 \,m$ long. The free end of the steel rod is maintained at $100^{\circ}C$ and that of the copper rod at $0^{\circ}C$. Assuming that the rods are perfectly insulated from the surroundings,the temperature at the junction of the two rods is ................... $^{\circ}C$.

In a steady state, the graph between temperature $(\theta)$ and distance $(x)$ from the hot end is:

Two ends of rods of length $L$ and radius $r$ of the same material are kept at the same temperature difference. Which of the following rods conducts the most heat?

If the thermal conductivity of aluminum is $0.5 \ cal/cm \cdot s \cdot ^\circ C$,then the temperature gradient required to conduct $10 \ cal/s \cdot cm^2$ in the steady state is ...... $^\circ C/cm$.