Which of the following cylindrical rods will coduct most heat when their ends are maintained at the same steady temperatures?
Length $1\ m$, radius $1\ cm$
Length $1\ m$, radius $2\ cm$
Length $2\ m$, radius $1\ cm$
Length $2\ m$, radius $2\ cm$
A wall has two layers $A$ and $B,$ each made of different material. Both the layers have the same thickness. The thermal conductivity for $A$ is twice that of $B$ and under steady condition, the temperature difference across the wall is $36\,^oC.$ The temperature difference across the layer $A$ is....... $^oC$
Certain quantity of water cools from $70\,^oC$ to $60\,^oC$ in the first $5\, minutes$ and to $54\,^oC$ in the next $5\, minutes$. The temperature of the surroundings is......... $^oC$
The two ends of a rod of length $L$ and a uniform cross-sectional area $A$ are kept at two temperatures $T _{1}$ and $T _{2}\left( T _{1} > T _{2}\right) .$ The rate of heat transfer, $\frac{ dQ }{ dt }$ through the rod in a steady state is given by
A hot liquid kept in a beaker cools from $80\,^oC$ to $70\,^oC$ in $2\, min$. If the surrounding temperature is $30\,^oC$, then the time of cooling of the same liquid from $60\,^oC$ to $50\,^oC$ ........ $\sec$
Newton's law of cooling is used in laboratory for the determination of the ...........