A block of metal is heated to a temperature much higher than the room temperature and allowed to cool in a room free from air currents. Which of the following curves correctly represents the rate of cooling
A body cools from $62\,^oC$ to $50\,^oC$ in $10\, minutes$ and to $42\,^oC$ in the next $10\, minutes$. The temperature of the surrounding is ........ $^oC$
A body cools from $62\,^oC$ to $50\,^oC$ in $10\, minutes$ and to $42\,^oC$ in next $10\, minutes$. The temperature of the surrounding is ........... $^oC$
Assuming the sun to be a spherical body of radius $R$ at a temperature of $TK$ , evaluate the total radiant power, incident on the earth, at a distance $r$ from the sun, is (Where $r_0$ is the radius of the earth and $\sigma $ is Stefan s constant.)
A black body, at a temperature of $227\,^oC$ radiates heat at a rate of $7\, cal\, cm^{-2} \,s^{-1}$. At a temperature of $727\,^oC$, the rate of heat radiated in the same $units$ will be ..... $unit$
A wall has two layers $A$ and $B$ , each made of a different material. Both the layers have the same thickness. The thermal conductivity of the material of $A$ is twice that of $B$ . Under thermal equilibrium, the temperature difference across the wall is $36\,^oC$. The temperature difference across the layer $A$ is ......... $^oC$