The temperature of a liquid drops from $365K$ to $361 K$ in $2$ minutes. Find the time during which temperature of the liquid drops from $344\;K$ to $342K$. Temperature of room is $293\;K$  ……. $\sec$

A hollow copper sphere $S$ and a hollow copper cube $ C$ , both of negligible thin walls of same area, are filled with water at $90°C$  and allowed to cool in the same environment. The graph that correctly represents their cooling is

A hot body, obeying Newton's law of cooling is cooling down from its peak value $80\,^oC$ to an ambient temperature of $30\,^oC$ . It takes $5\, minutes$ in cooling down from $80\,^oC$ to $40\,^oC$.  ……..  $\min.$ will it take to cool down from $62\,^oC$ to $32\,^oC$ ? (Given $ln\, 2\, = 0.693, ln\, 5\, = 1.609$)

A sphere and a cube of same material and same volume are heated upto same temperature and allowed to cool in the same surroundings. The ratio of the amounts of radiations emitted will be

A body initially at $80^o C$ cools to $64^o C$ in $5$ minutes and to $52^o C$ in $10 $ minutes. The temperature of the body after $15$ minutes will be …… $^oC$