Question

{"given":"Beta radiation ($\\beta^-$ decay) is a type of nuclear decay involving transformation of a nucleon.","key_observation":"In $\\beta^-$ decay, a neutron inside the nucleus transforms into a proton, an electron, and an antineutrino: $n \\rightarrow p + e^- + \\bar{\\nu}$. The emitted electron originates from this decay process.","option_analysis":[{"label":"(A)","text":"Inner orbit of an atom","verdict":"incorrect","explanation":"Electrons in inner orbits are bound electrons of the atom and are not emitted during nuclear beta decay. Beta emission is a nuclear process, not an atomic orbital process."},{"label":"(B)","text":"Free electron existing in the nucleus","verdict":"incorrect","explanation":"According to quantum mechanics, electrons do not exist freely inside the nucleus. The beta electron is created at the moment of decay."},{"label":"(C)","text":"Decay of a neutron in the nucleus","verdict":"correct","explanation":"During $\\beta^-$ decay, a neutron transforms into a proton and emits an electron (and an antineutrino): $n \\rightarrow p + e^- + \\bar{\\nu}$. This increases the atomic number $Z$ by 1 while mass number $A$ remains unchanged."},{"label":"(D)","text":"A photon escaping from the nucleus","verdict":"incorrect","explanation":"Photons escaping from the nucleus correspond to gamma ($\\gamma$) radiation, not beta radiation. These are entirely different types of nuclear emissions."}],"answer":"(C)","formula_steps":[]}