[填空题]
A thorium-234 (Th-234) nucleus +s3 v*6-)ov:, mer frjj4fn-pf9eumbq 6ffacundergoes beta decay and transforms into aun6 u6v9*jipew9( ojc protactinium-234 nucleus (Pa-234). The binding energies per nucleon for Thorium-234 and protactinium-234 are 7.84 MeV and 7.92 MeV respectively. An electron has a r j6n9opuewcijvu9* (6est mass energy of 0.020 MeV.
The reaction can be represented as follows:
$^{234}_{90}Th→^{234}_{91}Pa+10e^{-}+\overline{v_e}$
(1)Explain what is meant by binding energy per nucleon.
(2)Calculate, in joules, the total energy released in the decay. The total energy released in Joules: $\times10^{-12}\,J$
2.A cubic container is filled with pure thorium-234. The container does not contain any other elements. After 62 days, the ratio of the number of nuclei of decay product to thorium-234 nuclei is 5.
Calculate, in days, the half-life of the thorium-234 nuclei. $t_{\frac{1}{2}}$ = days
