Answer: [tex]t_\frac{1}{2}[/tex]
Explanation:-
1. Activation energy is the extra energy required by the reactants to cross the energy barrier and convert to products. It is designated by the symbol [tex]E_a[/tex].
2. Half life is the time taken by a reactant to reduce to its original concentration. It is designated by the symbol [tex]t_\frac{1}{2}[/tex].
3. Alpha decay: In this process, alpha particles is emitted when a heavier nuclei decays into lighter nuclei. The alpha particle released has a charge of +2 units.
[tex]_Z^A\textrm{X}\rightarrow _{Z-2}^{A-4}+_2^4\alpha[/tex]
4. Beta-decay: In this process, a neutron gets converted into a proton and an electron releasing a beta-particle. The beta particle released carries a charge of -1 units.
[tex]_Z^A\textrm{X}\rightarrow _{Z+1}^A\textrm{Y}+_{-1}^0\beta[/tex]
