240 HW 11 Fall 2016
Name_______________________________________
1) If a Σ- at rest decays into an n and "- , what is the total kinetic energy of the decay products? (The masses of
2
Σ- , n and "- are 1197, 940, and 140 MeV/c respectively.)
2) A hypothetical particle has mass 510 MeV/c2. If such a particle at rest decays into two gamma-ray photons,
what is the wavelength of each photon?
(Note: e = 1.602 × 10-19 C, c = 2.998 × 108 m/s, and h = 6.626 × 10-34 J ∙ s.)
3) Consider the fusion reaction:
2 H + 2 H + 2 H → 4 He + 1 H + 1 n
1
1
1
2
1
0
The atomic masses are:
2 H, 2.01410 u ; 4 He, 4.00260 u; 1 H, 1.00783 u; and 1 n, 1.008665 u,
1
2
1
0
where 1u = 1.6606 × 10-27 kg. What mass of deuterium { 2 H} fuel is used up in producing 5.6 × 1015 J of
1
energy by this reaction?
4) The unstable isotope 234Th decays by β emission with a half-life of 24.5 days. If the initial decay rate of the
sample is 6.2 × 1017 decays per second, what is the decay rate after 37 days?
1
Answer Key
Testname: 240HW11NUCLEAR
1) 117 MeV
2) 4.86 × 10 -15 m
3) 1.6 × 10 1 kg
4) 2.2 × 10 17 decays per second
2