Transmission Of Heat Question 180
Question: A body cools from $ 60^{o}C $ to $ 50^{o}C $ in 10 minutes. If the room temperature is $ 25^{o}C $ and assuming Newton’s law of cooling to hold good, the temperature of the body at the end of the next 10 minutes will be
[MP PMT/PET 1998; BHU 2000; Pb. PMT 2001]
Options:
A) $ {{38.5}^{o}}C $
B) $ 40^{o}C $
C) $ {{42.85}^{o}}C $
D) $ 45^{o}C $
Show Answer
Answer:
Correct Answer: C
Solution:
$ \frac{60-50}{10}=K( \frac{60+50}{2}-25 ) $ ?..(i) $ \frac{50-\theta }{10}=K[ \frac{50+\theta }{2}-25 ] $ ?..(ii) On dividing, we get $ \frac{10}{50-\theta }=\frac{60}{\theta }\Rightarrow \theta ={{42.85}^{o}}C $
BETA
