a beam of invisible particles or waves emitted by a source – the process of transmission of energy in corpuscular (α, β, … particles, …) or electromagnetic form (visible light, ultraviolet, infrared, X, γ, …)
a beam of invisible particles or waves emitted by a source – the process of transmission of energy in corpuscular (α, β, … particles, …) or electromagnetic form (visible light, ultraviolet, infrared, X, γ, …)