-ей, мн. Физ.
Поток бета-частиц (электронов или позитронов), испускаемых атомными ядрами при их бета-распаде.
бе́та-лучи́
Поток бета-частиц.
бета-лучи, бета-лучей
"Honest disagreement is often a good sign of progress." Mahatma Gandhi
"Sweet mercy is nobility's true badge." William Shakespeare
"It is better to know some of the questions than all of the answers." James Thurber
"This is the most joyful day that ever I saw in my pilgrimage on earth." Donald Cargill