Prevost’s theory of exchanges in thermal radiation Evaluate the statement: Every body, regardless of its temperature, continuously emits radiation to and receives radiation from its surroundings at the same time.

Introduction / Context:
Prevost’s theory of exchanges provides an intuitive basis for radiative heat transfer. It clarifies that emission and absorption are simultaneous processes and that net heat flow by radiation depends on temperature differences and surface properties.

Given Data / Assumptions:

• Any real surface at finite temperature emits thermal radiation.
• The same surface can absorb incident radiation from its surroundings.
• Vacuum is not required; radiation propagates through transparent media as well.

Concept / Approach:
According to Prevost, all bodies emit radiation continuously as a function of their temperature and emissivity, and they also receive radiation from other bodies. Net radiative exchange equals emission minus absorption. A cooler body can still emit radiation; it simply absorbs more than it emits if surrounded by hotter surfaces, resulting in a net gain.

Step-by-Step Solution:

Verification / Alternative check:
Kirchhoff’s law at equilibrium (ε = α) and the Stefan–Boltzmann relation support the continuous nature of emission and the role of absorption; at equilibrium net exchange is zero though two-way exchange persists.

Why Other Options Are Wrong:

“False” or restricted cases contradict the universal nature of radiative emission for T > 0 K.Polished metals and vacuum conditions are not prerequisites; they only alter amounts or paths of radiation.

Common Pitfalls:
Equating “net heat loss” with “no emission” when surroundings are hotter; remember both emission and absorption occur, and net direction depends on relative intensities.

Final Answer:

True