also half life
(half-lives)
The ~ of a radioactive substance is the amount of time that it takes to lose half its radioactivity.
N-COUNT
also half life
(half-lives)
The ~ of a radioactive substance is the amount of time that it takes to lose half its radioactivity.
N-COUNT
Collins COBUILD. Толковый словарь английского языка для изучающих язык Коллинз COBUILD (международная база данных языков Бирмингемского университета) . 2012