For heat to flow from one end to the other in a solid,it is necessary to have:

What is temperature gradient? When is the temperature gradient considered positive and when is it considered negative?

Why are snow particles poorer conductors of heat than ice?

Heat is flowing through a conductor of length $l$ from $x = 0$ to $x = l$. If its thermal resistance per unit length is uniform,which of the following graphs correctly represents the variation of temperature $T$ with distance $x$?

Snow is more heat insulating than ice,because

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 $^{\circ} C$)