Question 1
The initial decay rate of a nuclide is 1.77 × 10
12/m. After 7.63 d, the decay rate is 1.82 × 10
11/m. What is the half-life of the isotope?
◦ 139 d
◦ 0.298 d
◦ 0.207 d
◦ 2.32 d
◦ 2.50 d
Question 2
The masses of

He,

Li and

B are 4.0015, 6.0135 and 10.0102 amu, respectively. Splitting a boron-10 nucleus to helium-4 and lithium-6 would:
◦ absorb energy
◦ evolve energy
◦ result in no energy change
◦ boron cannot be split
◦ cannot be determined