$A$ brass boiler has a base area of $0.15\; m^{2}$ and thickness $1.0\; cm$. It boils water at the rate of $6.0\; kg/min$ when placed on a gas stove. Estimate the temperature (in $^oC$) of the part of the flame in contact with the boiler. Thermal conductivity of brass $= 109\; J s^{-1} m^{-1} K^{-1}$; Heat of vaporisation of water $= 2256 \times 10^{3}\; J kg^{-1}$.

Two metal cubes $A$ and $B$ of the same size are arranged as shown in the figure. The ends of the combination are maintained at the indicated temperatures. The arrangement is thermally insulated. If the thermal conductivities of $A$ and $B$ are $300 \, W/m \, ^\circ C$ and $200 \, W/m \, ^\circ C$ respectively,find the temperature $t$ at the junction when the steady state is reached.

Two rods,one made of copper and the other of steel,having the same length and cross-sectional area,are joined together. The thermal conductivity of copper is $385 \, J s^{-1} m^{-1} K^{-1}$ and that of steel is $50 \, J s^{-1} m^{-1} K^{-1}$. If the copper end is held at $100^{\circ} C$ and the steel end is held at $0^{\circ} C$,the junction temperature is ........... $^{\circ} C$ (Assuming no other heat losses).

On heating one end of a rod,the temperature of the whole rod will be uniform when

What is the temperature (in $^oC$) of the steel-copper junction in the steady state of the system shown in the figure? Length of the steel rod $= 15.0 \; cm,$ length of the copper rod $= 10.0 \; cm,$ temperature of the furnace $= 300^{\circ} C,$ temperature of the other end $= 0^{\circ} C.$ The area of cross-section of the steel rod is twice that of the copper rod. (Thermal conductivity of steel $= 50.2 \; J s^{-1} m^{-1} K^{-1};$ and of copper $= 385 \; J s^{-1} m^{-1} K^{-1}$)

For cooking the food,which of the following type of utensil is most suitable?