A body cools from 60$^\circ$C to 40$^\circ$C in 6 minutes. If, temperature of surroundings is 10$^\circ$C. Then, after the next 6 minutes, its temperature will be ____________$^\circ$C.
Answer (integer)
28
Solution
By average form of Newton's law of cooling $\frac{20}{6}=\mathrm{k}(50-10)$
<br/><br/>
$\frac{40-\mathrm{T}}{6}=\mathrm{K}\left(\frac{40+\mathrm{T}}{2}-10\right)$
<br/><br/>
From equations (i) and (ii)
<br/><br/>
$\frac{20}{40-\mathrm{T}}=\frac{40}{10+\mathrm{T} / 2}$
<br/><br/>
$10+\frac{\mathrm{T}}{2}=80-2 \mathrm{~T}$
<br/><br/>
$\frac{5 \mathrm{~T}}{2}=70 \Rightarrow \mathrm{T}=28^{\circ} \mathrm{C}$
About this question
Subject: Physics · Chapter: Properties of Solids and Liquids · Topic: Elasticity
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