The temperature at the surface of the Sun is approximately 5...

Name: Problem 40, Chapter 22: Physics for Scientists and Engineers with Modern Physics
Uploaded: 2020-08-10T11:20:05-08:00
Duration: 1 min 52 s
Channel: Khoobchandra Agrawal
Description: The temperature at the surface of the Sun is approximately 5 700 K, and the temperature at the surface of the Earth is approximately 290 K. What entropy change occurs when 1 000 J of energy is transferred by radiation from the Sun to the Earth?

The temperature at the surface of the Sun is approximately 5 700 K, and the temperature at the surface of the Earth is approximately 290 K. What entropy change occurs when 1 000 J of energy is transferred by radiation from the Sun to the Earth?

Key Concepts

Second Law of Thermodynamics

The second law of thermodynamics states that the total entropy of an isolated system can never decrease over time, and that energy transfers have inherent inefficiencies that lead to an overall increase in entropy. In the process of transferring energy from a high-temperature body to a low-temperature body, while the entropy of the hot source decreases, the increase in entropy of the cold sink is larger, resulting in a net positive change in entropy for the overall system.

Thermodynamic Reservoirs

Thermodynamic reservoirs are idealized systems that remain at a constant temperature despite the exchange of energy. In this context, the Sun and the Earth can be considered as reservoirs with very high and low temperatures, respectively. When energy is transferred from one reservoir (the Sun) to another (the Earth), each reservoir experiences a change in entropy calculated by dividing the energy exchanged by its temperature.

Entropy

Entropy is a thermodynamic property which quantifies the degree of disorder or randomness in a system. In processes involving energy transfer, it provides a measure of the dispersal of energy, indicating the natural tendency of systems to move towards equilibrium. Changes in entropy are used to evaluate whether a process is reversible or irreversible, and they play a crucial role in determining the direction of spontaneous processes.

Heat Transfer via Radiation

Heat transfer by radiation involves the transmission of energy through electromagnetic waves. Unlike conduction or convection, radiative heat transfer does not require a medium; energy can be exchanged between bodies at different temperatures through the emission and absorption of photons. This fundamental mechanism is essential in astrophysical contexts as well as in everyday phenomena.

Transcript

Please give Ace some feedback