Question

The table below gives the observations reported by two students $X$ and $Y$ for an experiment on the study of temperature-time graph. The experiment is likely to have been performed correctly by

Time (in min)	Student $X$	Student $Y$
0	${61}^{o}C$	${61}^{o}C$
2	${60.5}^{o}C$	${59.0}^{o}C$
4	${60.0}^{o}C$	${58.0}^{o}C$
6	${59.0}^{o}C$	${57.5}^{o}C$
8	${58.0}^{o}C$	${57.0}^{o}C$
10	${56.5}^{o}C$	${56.5}^{o}C$
12	${54.0}^{o}C$	${56.0}^{o}C$

• A. $X$
• B. $Y$
• C. both $X$ and $Y$
• D. neither $X$ and $Y$

Answer 1

The correct option is B $Y$

The experiment performed by student $Y$ is in accordance with the Sir Newton's law of cooling , therefore it is correct . Sir Newton's law of cooling states that the rate of cooling (heat loss) of a body is directly proportional to the difference in temperatures of the body ($T$) and surrounding ($T_o$) i.e.

$E\propto (T-T_o)$ ,

it means , rate of cooling will be faster initially because initially the temperature difference is large , with increase in time the difference of temperatures decreases hence the rate of cooling also decreases . This result is obtained from the experiment done by student $Y$ , so he is correct .