1. Tardigrade
  2. Question
  3. Physics
  4. Two circular discs A and B with equal radii are blackened. They are heated to same temperature and are cooled under identical conditions. What inference do your draw from their cooling curves?

Question Error Report

Thank you for reporting, we will resolve it shortly

Back to Question

Q. Two circular discs $A$ and $B$ with equal radii are blackened. They are heated to same temperature and are cooled under identical conditions. What inference do your draw from their cooling curves?Physics Question Image

Thermal Properties of Matter

Solution:

When a body cools by radiation, the rate of cooling is given by:
$\frac{d \theta}{d t}=-\frac{e A \sigma}{m s}\left(\theta^{4}-\theta_{0}^{4}\right)$
-ve sign shows that temperature decreases, i.e., the body cools, $s$ is the specific heat of material and $\theta_{0}$ is the surrounding temperature
or $\frac{d \theta}{d t} \propto \frac{1}{s}$
i.e., rate of cooling $(R=d \theta / d t)$ is inversely proportional to the specific heat of material. For a, rate of cooling is large, therefore, specific heat of $A$ is smaller.