$A$ piece of glass is heated to a high temperature and then allowed to cool. If it cracks,a probable reason for this is the following property of glass:

The radius of a conductor increases uniformly from the left end to the right end as shown in the figure. The material of the conductor is isotropic,and its curved surface is thermally isolated from the surroundings. Its ends are maintained at temperatures $T_1$ and $T_2$ $(T_1 > T_2)$. If,in a steady state,the heat flow rate is equal to $H$,then which of the following graphs is correct?

$Assertion:$ Two thin blankets put together are warmer than a single blanket of double the thickness.
$Reason:$ Thickness increases because of the air layer enclosed between the two blankets.

The temperature gradient in a rod of length $75 \ cm$ is $40^{\circ} C/m$. If the temperature of the cooler end of the rod is $10^{\circ} C$,then the temperature of the hotter end is: (in $^{\circ} C$)

What is heat transfer? Write its modes. In which mode,medium is not required?

In a steady state of thermal conduction,the temperatures of the ends $A$ and $B$ of a $20 \, cm$ long rod are $100^\circ C$ and $0^\circ C$ respectively. What will be the temperature of the rod at a point at a distance of $6 \, cm$ from the end $A$ of the rod (in $^\circ C$)?