$A$ 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........... $s$

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

Two solid spheres $A$ and $B$ made of the same material have radii $r_A$ and $r_B$ respectively. Both the spheres are cooled from the same temperature under the conditions valid for Newton's law of cooling. The ratio of the rate of change of temperature of $A$ and $B$ is :

Two liquids of equal volume are cooled under identical conditions from $60^{\circ}C$ to $50^{\circ}C$ in $324 \; sec$ and $810 \; sec$ respectively. If the ratio of their specific heats is $3:4$,find the ratio of their densities. (The water equivalent of the calorimeter is negligible.)

An object is cooled from $75^{\circ}C$ to $65^{\circ}C$ in $2$ minutes in a room at $30^{\circ}C$. The time taken to cool another object from $55^{\circ}C$ to $45^{\circ}C$ in the same room in minutes is

An ordinary body cools from $4\theta$ to $3\theta$ in $t$ minutes. The temperature of the body after the next $t$ minutes is (Assume Newton's law of cooling and room temperature as $\theta$).