radioactive constant n.
See decay constant.
noun, Physics. 1. (def 8). noun 1. disintegration of a nucleus that occurs spontaneously or as a result of electron capture. One or more different nuclei are formed and usually particles and gamma rays are emitted Sometimes shortened to decay Also called disintegration radioactive decay (rā’dē-ō-āk’tĭv) The spontaneous transformation of an unstable atomic nucleus into […]
noun 1. a motor-vehicle tire in which the plies or cords run from one bead to the other at right angles to both beads.
noun, Biology. 1. a basic body plan in which the organism can be divided into similar halves by passing a plane at any angle along a central axis, characteristic of sessile and bottom-dwelling animals, as the sea anemone and starfish. noun 1. a type of structure of an organism or part of an organism in […]
- Radioactive isotope
radioactive isotope n. An isotope having an unstable nucleus that decomposes spontaneously by emission of a nuclear electron or helium nucleus and radiation, thus achieving a stable nuclear composition.