Four rods of silver,copper,brass,and wood are of the same shape. They are heated together after wrapping a paper on each. The paper will burn first on:

Ice starts forming in a lake with water at $0^{\circ}C$ when the atmospheric temperature is $-10^{\circ}C$. If the time taken for $1 \; cm$ of ice to form is $7$ hours,then the time taken for the thickness of ice to change from $1 \; cm$ to $2 \; cm$ is:

The heat is flowing through a rod of length $50 \ cm$ and area of cross-section $5 \ cm^2$. Its ends are respectively at $25^\circ C$ and $125^\circ C$. The coefficient of thermal conductivity of the material of the rod is $0.092 \ kcal/m \cdot s \cdot ^\circ C$. The temperature gradient in the rod is

Write a note on a double-walled flask or a thermos.

If it takes $7 \, h$ to form a $1 \, cm$ thick layer of ice on a pond at $0^o C$,how many hours will it take for the thickness of the ice layer to increase from $1 \, cm$ to $2 \, cm$?

Woollen clothes are used in winter season because woolen clothes