A hot liquid is filled in a container and kept in a room of temperature of $25^{\circ} \mathrm{C}$.

Question

A hot liquid is filled in a container and kept in a room of temperature of $25^{\circ} \mathrm{C}$. The liquid emits heat at the rate of $200 \mathrm{Js}^{-1}$ when its temperature is $75^{\circ} \mathrm{C}$. When the temperature of the liquid becomes $40^{\circ} \mathrm{C}$, the rate of heat loss in $\mathrm{Js}^{-1}$ is\

Professor PC Thomas Classes · Answer

Applying Newton's law of cooling\ $\frac{\mathrm{Ms}(75-25)}{\mathrm{dt}}=200 \mathrm{~J} / \mathrm{s}$\ $\frac{\mathrm{Ms}}{\mathrm{dt}}(40-25)=\mathrm{x} 	herefore \mathrm{x}=\frac{200}{50} 	imes 15=60 \mathrm{~J} / \mathrm{s}$\