A body takes $T$ minutes to cool from ${62^o}C$ to ${61^o}C$ when the surrounding temperature is ${30^o}C$. The time taken by the body to cool from ${70^o}$ to $({A_1}\,{\rm{and }}{A_{\rm{2}}})$ is
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(b) In first step
$\frac{{62 - 61}}{T} = K\,\left[ {\frac{{62 - 61}}{2} - 30^\circ } \right]$==> $\frac{1}{T} = K\,[81.5]$ ...$(i)$
In second step, suppose process takes $T'\min $ then
$\frac{{46 - 45.5}}{{T'}} = K\,\left[ {\frac{{46 - 45.5}}{2} - 30} \right]$$\frac{{0.5}}{{T'}} = K\,[15.75]$ ...$(ii)$
On diving equation $(i)$ and $(ii)$ $\frac{{2T'}}{T} = 2$==> $T' = T$
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