$A$ body cools down from $75^{\circ}C$ to $60^{\circ}C$ in $10 \text{ minutes}$. It will cool down from $65^{\circ}C$ to $55^{\circ}C$ in a time:

In an experiment to verify Newton's law of cooling,a graph is plotted between the temperature difference $(\Delta T)$ of the water and surroundings and time as shown in the figure. The initial temperature of water is taken as $80^{\circ}C$. The value of $t_{2}$ as mentioned in the graph will be...........

$A$ 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?

Two spheres of the same metal have radii $r$ and $2r$. They are heated to the same temperature and placed in the same environment. The ratio of their rates of cooling will be:

$A$ liquid of mass $250 g$ is kept warm in a vessel using an electric heater. The liquid is maintained at $57^{\circ} C$ when the power supplied by the heater is $30 W$ and the surrounding temperature is $27^{\circ} C$. As the heater is switched off,it takes $10 s$ for the temperature of the liquid to fall from $47^{\circ} C$ to $46.9^{\circ} C$. The specific heat capacity of the liquid is:

$A$ very thin metallic shell of radius $r$ is heated to temperature $T$ and then allowed to cool. The rate of cooling of the shell is proportional to ........