Properties Of Solids And Liquids Question 456
Question: Consider two hot bodies $ {{B} _{1}} $ and $ B _{2} $ which have temperatures $ 109{}^\circ C $ and $ 89{}^\circ C $ respectively at t=0. The temperature of the surroundings is$ 49{}^\circ C $ . The ratio of the respective rates of cooling $ R _{1} $ and $ R _{2} $ of these two bodies at t = 0 will be
Options:
A) $ R _{1}:R _{2}=3:2 $
B) $ R _{1}:R _{2}=5:4 $
C) $ R _{1}:R _{2}=2:3 $
D) $ R _{1}:R _{2}=4:5 $
Show Answer
Answer:
Correct Answer: A
Solution:
[a] Initially at t=0 Rate of cooling (R) $ \propto $ Fall in temperature of body $ \Rightarrow \frac{R _{1}}{R _{2}}=\frac{{\theta _{1}}-{\theta _{0}}}{{\theta _{2}}-{\theta _{0}}}=\frac{100-40}{80-40}=\frac{3}{2} $
