Question

Which of the following cannot be emitted by radioactive substance during their decay?

• A. protons
• B. neutrinos
• C. helium nuclei
• D. electrons

Answer 1

Answer: (A)

The nuclei of the radioactive substances emit various particles as shown below.
Alpha decay ${}_z^{A}X\to {}_{z-2}^{A-4}Y+{}_2^{4}He$
Beta decay ${\left(B^{-}\right)}_z^{A}X{\to }_{z+1}^{A}Y+e^{e-}+\overline{v}$
Beta decay ${\left(B^{+}\right)}_A^{Z}X{\to }_{z-1}^{A}Y+e^{+}+v$
Electron capture ${}_z^{A}X+e^{-}\to {}_{z-1}^{A}Y+v$
Gamma decay ${}_z^{A}X\to {}_Z^A+v$
As we see above in radioactive decay protons & neutrons are not emitted.