Radioactivity

Definitions

1. Spontaneous emission of ionizing radiation as a consequence of a nuclear reaction, or directly from the breakdown of an unstable nucleus.
   uncountable, usually
2. The radiation so emitted; including gamma rays, alpha particles, neutrons, electrons, positrons, etc.
   uncountable, usually

Equivalents

Examples

“Today, no one would intentionally smear radioactive materials on their face⟳, but in 1933, the dangers of radioactivity were not yet fully understood.”

CEFR level