In: Physics
1. A typical α-decay from a parent nucleus AZX may be indicated as :
Group of answer choices
AZX → (A−4)(Z − 2) Y + 42He
AZX → (A+4)(Z+2) Y + 22He
AZX → (A−4)Z Y + 42He
AZX → (A−4)(Z+2) Y + 42He
2. An element of atomic number 83 in a relatively higher energy state decays radioactively to an element of atomic number 84 with lower energy level. This must include
Group of answer choices
an α emission
a β emission
a γ emission
a β & γ emission
3. The half- life of radium-226 is 1.6 × 103 . If a sample initially contains 3.0 × 1016 such nuclei, what is the number of radioactive radium-226 nuclei remaining after 4.8 × 103 years?
Group of answer choices
2.25 × 1012
3.75 × 1016
2.2 × 1016
3.75 × 1015