Consider two hot bodies ${B_1}$ and ${B_2}$ which have temperatures ${100^o}C$ and ${80^o}C$ respectively at $t = 0$. The temperature of the surroundings is ${40^o}C$. The ratio of the respective rates of cooling ${R_1}$ and ${R_2}$ of these two bodies at $t = 0$ will be
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(a) Initially at $t = 0$
Rate of cooling $(R)$ $\propto$ Fall in temperature of body ($\theta -\theta_0$)
==> $\frac{{{R_1}}}{{{R_2}}} = \frac{{{\theta _1} - {\theta _0}}}{{{\theta _2} - {\theta _0}}} = \frac{{100 - 40}}{{80 - 40}} = \frac{3}{2}$
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