Question

According to Rayleigh and Jeans the black body radiation in the cavity is system of (A) progressive electromagnetic waves (B) standing electromagnetic waves (C) electromagnetic waves of discrete (D) standing waves in lattice frequencies

Short answer

According to Rayleigh and Jeans, the black body radiation in a cavity is described by (B) standing electromagnetic waves. This is due to the boundary conditions inside the cavity and the Rayleigh-Jeans Law, which is based on classical electromagnetic wave theory.

Step-by-step solution

Understanding the Rayleigh-Jeans Law

The Rayleigh-Jeans Law is an attempt to describe the spectral distribution of energy in a black-body radiation. It gives the energy density of radiation in a cavity per unit frequency range. This law is based on classical electromagnetic wave theory, combined with statistical mechanics, and is given by the expression: \[u(\nu, T) = \frac{8\pi\nu^2}{c^3} k_BT\] Where \(u(\nu, T)\) is the energy density per unit frequency, \(\nu\) is the frequency, \(T\) is the temperature, \(c\) is the speed of light, and \(kB\) is the Boltzmann constant.

Identifying the nature of waves from the Rayleigh-Jeans Law

Since Rayleigh-Jeans Law is based on classical electromagnetic wave theory, it implies that the black body radiation is essentially a result of the interaction between electromagnetic waves bouncing around within the cavity. The waves will form standing wave patterns due to the boundary conditions inside the cavity.

Choose the correct description

According to our analysis of the Rayleigh-Jeans Law and its implications for black-body radiation in a cavity, the correct answer should be: (B) standing electromagnetic waves