Transmission Of Heat Question 186
Question: A body cools in 7 minutes from $ 60^{o}C $ to $ 40^{o}C $ What time (in minutes) does it take to cool from $ 40^{o}C $ to $ 28^{o}C $ if the surrounding temperature is $ 10^{o}C $ ? Assume Newton’s Law of cooling holds
[Kerala (Engg.) 2001]
Options:
A) 3.5
B) 11
C) 7
D) 10
Show Answer
Answer:
Correct Answer: C
Solution:
In first case $ \frac{60-40}{7}=K[ \frac{60+40}{2}-10 ] $ ?.(i) In second case $ \frac{40-28}{t}=K[ \frac{40+28}{2}-10 ] $ ?.(ii) By solving $ t=7 $ minutes
BETA
