Exam 30: Nuclear Physics

A summary of the nuclear reactions that power our sun is 4p → ⁴He + 2e^-, with masses of 938.272 MeV/c² for a proton, 3727.38 MeV/c² for the helium nucleus, and 0.511 MeV/c² for each electron. How much energy is released by each of these reactions?

The symbol for a certain isotope of radium is $^{226}_{88}$ Ra. How many nucleons are there in the nucleus of this isotope?

The mass number of an atom is equal to the number of what particles in the nucleus?

In the nuclear reaction $^{38}_{19} K + ^{1}_{1}H → X + ^{38}_{20} Ca$ , what is X?

A radioactive isotope of atomic number Z emits an alpha particle, and the daughter nucleus then emits a beta-minus particle. What is the atomic number of the resulting nucleus?

The neutral deuterium atom, $^{2}_{1}$ H, has a mass of 2.014102 u; a neutral ordinary hydrogen atom has a mass of 1.007825 u; a neutron has a mass of 1.008665 u; and a proton has a mass of 1.007277 u. What is the binding energy of the deuterium nucleus? (1 u = 931.5 MeV/c²)

$^{223} _{87}Fr$ decays to $^{223}_{88}$ Ra by emitting what kind of nuclear radiation?

Time (days) 0 2 6 11 19 30 Counts per Minute 1000 899 726 556 356 200 In a laboratory accident, a work area is contaminated with radioactive material. Health physicists monitor the area during a 30-day period and obtain the data shown in the table. The accident occurred at time t = 0 days. They determine that it will not be safe for workers to enter the area until the radioactivity level has dropped to 16 counts per minute. Of the choices listed, which one is the earliest time after the accident that workers could safely return?

The maximum permissible workday dose for occupational exposure to radiation is 11 mrem. A 77-kg laboratory technician absorbs 2.3 mJ of 0.5-MeV gamma rays in a work day. The relative biological effectiveness (RBE) for gamma rays is 1.00. What is the number of gamma-ray photons absorbed by the technician in a workday?

In a head-on collision, an alpha particle (Z = 2) of energy $8.20 \mathrm { MeV }$ bounces straight back from a nucleus of charge $80.0 \mathrm { e } .$ How close were the centers of the objects at closest approach? (1 eV = 1.60 × 10^-19 J, e = 1.60 × 10^-19 C, 1/4πε₀ = 8.99 × 10⁹ N ∙ m²/C²)

A sodium-22 nucleus, $^{22}_{11} Na$ , decays into a neon-22 nucleus, $^{22}_{10}Ne$ , and one other particle. What is the other particle?

Consider the nuclear reaction: ⁷Li + ¹p → ⁴He + ⁴He. The known atomic masses are ⁷Li: 7.016005 u $^{4} _{2} He$ : 4.002603 u ¹p: 1.007825 u What is the Q-value (or reaction energy) of this reaction? (1 u = 931.5 MeV/c²)

When a neutron collides with a uranium-235 nucleus it can induce a variety of fission reactions. One such reaction is $^{235}_{92}$ U + $^{1}_{0}$ n → $^{140}_{54}$ Xe + $^{94}_{38}$ Sr + 2 $^{1}_{0}$ n The following mass values are known: $^{140}_{54}$ Xe: 139.921620 u $^{94}_{38}$ Sr: 93.915367 u $^{235}_{92}$ U: 235.043924 u $^{1}_{0}$ n: 1.008665 u How much energy is released in this reaction? (1 u = 931.5 MeV/c²)

Fermium-253 has a half-life of 3.00 days. If a sample of fermium originally has 7.37 × $10^7$ nuclei, how long will it take for there to be only 3.36 × $10^6$ fermium-253 nuclei left in this sample?

A carbon-14 nucleus decays to a nitrogen-14 nucleus by beta-minus decay. How much energy (in MeV) is released if carbon-14 has a mass of 14.003242 u and nitrogen-14 has a mass of 14.003074 u? (1 u = 931.5 MeV/c²)

Write the standard nuclear notation for the following nuclei: hydrogen-2, sulfur-33, and lead-207.

The mean life (time constant) of radon-222 is 5.526 d. If a sample of radon initially contains 6.00 × 10⁸ radon atoms, how many of them are left after 10.0 d?

A beryllium-8 nucleus at rest undergoes double alpha decay as follows: $^{8}_{4}$ Be → $^{4}_{2}$ He + $^{4}_{2}$ He The known atomic masses are: $^{4}_{2}$ He: 4.002603 $^{8}_{4}$ nd{array}\)Be: 8.005305 u What is the kinetic energy of each departing alpha particle? (1 u = 931.5 MeV/c²)

A radioactive substance containing 4.0 × 10¹⁶ unstable atoms has a half-life of 2.0 days. What is its activity (in curies, Ci) after 1.0 day? (1 Ci = 3.70 × 10¹⁰ Bq)

Consider the nuclear reaction $^{14} _{7} N + ^{4}_{2} He → ^{17} _{8} O + ^{1} _{1} H$ . The known atomic masses are $^{14}_{7} N: 14.003074 u\ ^{4}_{2} He: 4.002603 u\ ^{1} _{1} H: 1.007825 u\ ^{17}_{8} O$ : 16.999131 u What is the Q-value (or reaction energy) of this reaction? (1 u = 931.5 MeV/c²)