A bowl filled with very hot soup cools from $98^{\circ}\,C$ to $86^{\circ}\,C$ in $2$ minutes when the room temperature is $22^{\circ}\,C$. $..........\,minutes$ long it will take to cool from $75^{\circ}\,C$ to $69^{\circ}\,C$ ?

A cup of tea cools from ${80^0}C$ to ${60^o}C$ in one minute. The ambient temperature is ${30^o}C$. In cooling from ${60^o}C$ to ${50^o}C$ it will take ....... $\sec$

A sphere at temperature $600\,K$ is placed in an environment of temperature is $200\,K$ . Its cooling rate is $H$ . If its temperature reduced to $400\,K$ then cooling rate in same environment will become

On what does the proportionality constant depends given in Newton's law of cooling.

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

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 ...... $\min.$