Question

What is the temperature range up to which Newton's law of cooling holds good?

Answer 1

Newton's law of cooling

• It states that the rate of heat loss from a body is directly related to the temperature difference between the body & its surroundings, provided the difference is small.
• According to Newton's law of cooling, the rate of loss of heat, that is $–\mathrm{dQ}/\mathrm{dt}$ of the body is directly proportional to the difference of temperature is, $\mathrm{\Delta T}=({\mathrm{T}}_2–{\mathrm{T}}_1)$ of the body and the surroundings.

• The rate of loss of heat due to convection is proportional to the temperature difference for small temperature differences only.
• Hence, Newton's law of cooling holds good only if the temperature difference between the body and the surroundings is less than $10°\mathrm{C}$ .