A) 5 minutes
B) Lesser than 5 minutes
C) Greater than 5 minutes
D) Lesser or greater than 5 minutes depending upon the density of the liquid
Correct Answer: C
Solution :
According to Newton's law of cooling Rate of cooling µ mean temperature difference. Initially, mean temperature difference \[=\left( \frac{70+60}{2}-{{\theta }_{0}} \right)=(65-{{\theta }_{0}})\] Finally, mean temperature difference \[=\left( \frac{60+50}{2}-{{\theta }_{0}} \right)=(55-{{\theta }_{0}})\] In second case mean temperature difference decreases, so rate of fall of temperature decreases, so it takes more time to cool through the same range.You need to login to perform this action.
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