Description : Forged documents are detected by – (1) ultraviolet rays (2) infra-red rays (3) beta rays (4) gamma rays
Last Answer : (1) ultraviolet rays Explanation: Old postcards, books, signs, photos and other paper products made before the late 1930s rarely glow under a black light. Chemical bleaches and dyes used ... light. Knowing this helps to detect forged documents and distinguish reproductions in all types of ephemera.