A body takes $5$ minutes for cooling from ${50^o}C$ to ${40^o}C.$ Its temperature comes down to ${33.33^o}C$ in next $5$ minutes. Temperature of surroundings is ……. $^oC$ 

A body takes $10\, minutes$ to cool from $60\,^oC$ to $50\,^oC$. The temperature of surroundings is constant at $25\,^oC$. Then, the temperature of the body after next $10\, minutes$ will be approximately ……. $^oC$

A sphere of density $\rho $ , specific heat capacity $c$ and radius $r$ is hung by a thermally insulating thread in an enclosure which is kept at a lower temperature than the sphere. The temperature of the sphere starts to drop at a rate which depends upon the temperature difference between the sphere and the enclosure and the nature of the surface of sphere and is proportional to

A liquid cools down from ${70^o}C$ to ${60^o}C$ in $5$ minutes. The time taken to cool it from ${60^o}C$ to ${50^o}C$ will be

A body cools from $80^{\circ}\,C$ to $60^{\circ}\,C$ in $5$ minutes. The temperature of the surrounding is $20^{\circ} C$. The time it takes to cool from $60^{\circ}\,C$ to $40^{\circ}\,C$ is……….. $s$