Spread the love

Prevost’s Theory of Heat Exchange

Prevost’s Theory of Heat Exchange :- Prevost’s Theory of Heat Exchange is an important thermodynamic law, introduced in 1791 by Swiss scientist Peter Prevost. According to this theory, every object continuously exchanges thermal energy with its surroundings through the process of radiation at all temperatures (except at absolute zero, i.e., 0 Kelvin). This exchange continues indefinitely. The temperature difference between the object and its surroundings determines whether the object will experience a cooling effect or a heating effect.

Main Points :

(1). All objects radiate heat :
Every object, whatever its temperature, continuously radiates heat into its environment. This phenomenon occurs at all temperatures (except absolute zero).

(2). Exchange of heat :

(a). When a cold body is placed in the hot surrounding : The body radiates less energy and absorbs more energy from the surrounding, therefore the temperature of body increases.

(b). When a hot body placed in cooler surrounding : The body radiates more energy and absorb less energy from the surroundings. Therefore temperature of body decreases.

(c). When the temperature of a body is equal to the temperature of the surrounding : The energy radiated per unit time by the body is equal to the energy absorbed per unit time by the body, therefore its temperature remains constant.

(3). This theory applies independently :

This theory is not affected by the presence of other objects. That is, each object radiates heat independently, whether or not other objects are nearby.

Note :

(i). At absolute zero temperature (0 Kelvin), all atoms of a substance stay in their lowest energy state (ground state). At this temperature, no radiation is emitted by any substance. That’s why Prevost’s theory of heat exchange doesn’t apply at absolute zero. So, absolute zero is called the limiting temperature for Prevost’s theory.

(ii). Prevost’s theory helps us calculate how fast a body cools compared to its surroundings. It is used in Stefan-Boltzmann law and Newton’s law of cooling.

Prevost’s Theory of Heat Exchange

Like this: