MCQ
In β- emission from a radioactive substance, an electron is ejected. This electron comes from:
  • A
    The outermost orbit of an atom
  • B
    The inner orbits of an atom
  • C
    The surface of substance
  • The nucleus of an atom

Answer

Correct option: D.
The nucleus of an atom
The nucleus of an atom

Hint: Radioactivity is a nuclear phenomenon. Hence, electrons come out from the nucleus. Electron is created as a result of decay of one neutron into a proton inside the nucleus and it is not possible for the electron to stay inside the nucleus; thus, it is spontaneously emitted.

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