A cubic metal block of mass $5 \,kg$ and edge length $0.1 \,m$ and at an initial temperature of $100^{\circ} C$ is placed on a thermally insulating flat surface and exposed to air at $0^{\circ} C$. The time in seconds required to cool the block to a temperature of $37^{\circ} C$ is closest to

(Note: Specific heat of the metal $=500 \,J / kg /{ }^{\circ} C$; Heat transfer coefficient from block to air $=50 \,W / m ^2 /{ }^{\circ} C$ )

A solid cube and a solid sphere of the same material have equal surface area. Both are at the same temperature ${120^o}C$, then

According to Newton’s law of cooling, the rate of cooling of a body is proportional to ${(\Delta \theta )^n}$, where $\Delta \theta $ is the difference of the temperature of the body and the surroundings, and n is equal to

Two circular discs $A$ and $B$ with equal radii and equal mass are blackened. They are heated to same temperature and are cooled under identical conditions.What inference do you draw from their cooling curves ?

A body takes $5$ minutes to cool from $90^oC$ to $60^oC$. If the temperature of the surroundings is $20^oC$, the time taken by it to cool from $60^oC$ to $30^oC$ will be …… $\min.$