Duduli

Plasma frequency is the natural frequency at which electrons in a plasma oscillate collectively about their equilibrium positions. where, ● n = Electron number density ● e = Charge of an electron ● mₑ = Mass of an electron ● ε₀ = Permittivity of free space Plasma frequency increases with the square root of electron number density.

The partition function is a fundamental quantity in statistical mechanics that describes how a system is distributed among its possible energy states. For a system in thermal equilibrium: Z = Σ e⁻ᴱⁱ/ᵏᴮᵀ where Eᵢ is the energy of the ith state, kB is the Boltzmann constant, and T is the absolute temperature. The partition function is useful because many thermodynamic quantities, such as internal energy, entropy, and Helmholtz free energy, can be calculated from it.

Proof:-

Brewster’s Law states that when unpolarized light is incident on a transparent surface at the polarizing angle i_B, the reflected and refracted rays are perpendicular to each other.       tan i_B=μ where i_B is the Brewster angle and μ is the refractive index of the medium. Key point: At Brewster angle, the reflected light is completely plane polarized.