$A$ liquid cools from $50^oC$ to $45^oC$ in $5$ minutes and from $45^oC$ to $41.5^oC$ in the next $5$ minutes. The temperature of the surrounding is ...... $^oC$.

$A$ body cools from $75 \, ^\circ \text{C}$ to $65 \, ^\circ \text{C}$ in $2 \, \text{min}$ in a room at $30 \, ^\circ \text{C}$. How long will it take to cool from $55 \, ^\circ \text{C}$ to $45 \, ^\circ \text{C}$ in the same room?

On what does the proportionality constant depend in Newton's law of cooling?

For a small temperature difference between the body and the surroundings,the relation between the rate of loss of heat $R$ and the temperature of the body $\theta$ is depicted by:

Two identical beakers $A$ and $B$ contain equal volumes of two different liquids at $60\,^oC$ each and are left to cool down. The liquid in $A$ has a density of $8 \times 10^2\, kg/m^3$ and a specific heat of $2000\, Jkg^{-1}K^{-1}$,while the liquid in $B$ has a density of $10^3\, kg/m^3$ and a specific heat of $4000\, Jkg^{-1}K^{-1}$. Which of the following best describes their temperature versus time graph schematically? (Assume the emissivity of both the beakers to be the same.)

$A$ bucket full of hot water cools from $75^{\circ}C$ to $70^{\circ}C$ in time $T_1$,from $70^{\circ}C$ to $65^{\circ}C$ in time $T_2$,and from $65^{\circ}C$ to $60^{\circ}C$ in time $T_3$. Which of the following relations is correct?