The temperature of hot and cold end of a $20cm$ long rod in thermal steady state are at ${100^o}C$ and ${20^o}C$ respectively. Temperature at the centre of the rod is...... $^oC$

The temperature drop through each layer of a two layer furnace wall is shown in figure. Assume that the external temperature $T_1$ and $T_3$ are maintained constant and $T_1 > T_3$. If the thickness of the layers $x_1$ and $x_2$ are the same, which of the following statements are correct.

The area of the glass of a window of a room is $10\;{m^2}$ and thickness $2mm$. The outer and inner temperature are ${40^o}C$ and ${20^o}C$ respectively. Thermal conductivity of glass in $MKS$ system is $0.2$. The heat flowing in the room per second will be

A thin paper cup filled with water does not catch fire when placed over a flame. This is because

The ends of two rods of different materials with their thermal conductivities, radii of cross-sections and lengths all are in the ratio $1:2$ are maintained at the same temperature difference. If the rate of flow of heat in the larger rod is $4\;cal/\sec $, that in the shorter rod in $cal/\sec $ will be

The two ends of a metal rod are maintained at temperatures $100 ^o C$ and $110^o C$. The rate of heat flow in the rod is found to be $4.0\ J/s$. If the ends are maintained at temperatures $200^o\  C$ and $210^o\ C$, the rate of heat flow will be.... $J/s$