Exam 30: Nuclear Physics

When a stationary plutonium-239, $^{239}_{94}$ Pu, decays into uranium-235 plus an alpha particle, the energy released in the process is 5.24 MeV. The following masses are known: $^{4}_{2}$ He: 4.002603 u $^{235}_{92}$ U: 235.043924 u What is the mass of the $^{239}_{94}$ Pu nucleus, in amu? (1 u = 931.494 MeV/c²)

The carbon in our bodies was formed in nuclear reactions in long-dead stars. How much energy was released when the right number of ⁴He nuclei combined to make 12C? The mass of 4He is 3728.40 MeV/C2 and the mass of 12C is 11,177.93 MeV/C2.

A person receives an absorbed dose of protons of 20 millirads. The RBE of protons is 5. What is this person's equivalent dose in rem?

Rutherfordium-261 has a half-life of 1.08 min. How long will it take for a sample of rutherfordium to lose one-third of its nuclei?

If the half-life of a material is 45 years, how much of it will be left after 100 years?

The equation shows a fission reaction: $^{235}_{92}$ U + $^{1}_{0}$ n → $^{99}_{41}$ Nb + X + 4 $^{1}_{0}$ n What is the missing term X in the equation?

A β^- particle is also known as

Uranium-238 decays into thorium-234 plus an alpha particle. The known masses are $^{4}_{2}$ He: 4.002603 u $^{224}_{90}$ Th: 234.043583 u $^{238}_{90}$ U: 238.050786 u How much energy is released in this process? (1 u = 931.5 MeV/c²)

The nuclei of $^{4}_{2}$ He are also known as

Polonium-216 decays to lead-212 by emitting what kind of nuclear radiation?

The half-life of a radioactive material is 4.5 days. How many days are required for a sample, with an initial activity of 1.0 × 10⁵ Bq, to decay to an activity of 100 Bq?

Which of the following particles (or groups of particles) are made up of quarks?

The mean life (time constant) of rubidium-86 is 26.8 d. What is its half-life?

When a β⁺ particle is emitted from an unstable nucleus, the atomic number of the nucleus

A sample of wood has been recovered by an archaeologist. The sample is sent to a laboratory, where it is determined that the activity of the sample is 0.144 Bq/g. By comparing this activity with the activity of living organic matter, which is 0.230 Bq/g, the scientist determines how old the wood sample is, or more precisely, when the tree that the sample came from died. Carbon-14 has a half-life of 5730 years. If the activity of living matter has been constant over time, how old is the sample of wood?