Which constant is represented by the symbol 'k'?

The symbol 'k' is widely recognized in physics and thermodynamics as the Boltzmann Constant. This constant is fundamentally important in statistical mechanics, as it relates the average kinetic energy of particles in a gas with the temperature of the gas. Specifically, it ensures that the statistical behavior of particles can be understood in terms of temperature and energy, providing a bridge between macroscopic and microscopic physics.

The value of the Boltzmann Constant is approximately 1.38 x 10^-23 J/K, indicating the amount of energy per temperature increment per particle. Its role in the equation S = k ln(Ω), where S is entropy and Ω is the number of microstates, illustrates how it is used to describe the thermodynamic properties of systems at a molecular level.

In contrast, the Planck Constant, represented typically by 'h', pertains to the quantization of energy levels in quantum mechanics. The Gravitational Constant, often denoted by 'G', is vital for understanding gravitational interactions, particularly at astronomical scales. The term 'Einstein Constant' is not standard in physics, which makes it less relevant or recognized compared to the other constants mentioned.

Thus, the identification of 'k' with the Boltzmann Constant is a cornerstone