Exam 34: Geometric Optics

Radioactivity: The stability of C with respect to alpha, β⁺, and β^- decay is to be determined. Do not consider the possibility of decay by electron capture. The following atomic masses are known: He: 4.002603 u Be: 7.016928 u B: 11.009305 u C: 11.011433 u N: 11.026742 u The C nuclide is

Radioactive decay: A hospital patient has been given some (half-life = 8.04 d) which decays at 4.2 times the acceptable level for exposure to the general public. How long must the patient wait for the decay rate to reach the acceptable level? Assume that the material merely decays and is not excreted by the body.

Biomedicine: The maximum permissible workday dose for occupational exposure to radiation is 26 mrem. A 55-kg laboratory technician absorbs 3.3 mJ of 0.40-MeV gamma rays in a workday. The relative biological efficiency (RBE) for gamma rays is 1.00. What is the ratio of the equivalent dosage received by the technician to the maximum permissible equivalent dosage?

Nuclear fusion: The reaction ²H + ²H → ? ³H + ¹H releases 4.03 MeV of energy. If 1.0 kg of deuterium were to go through this reaction, how much energy would be produced? (1 eV = 1.60 × 10^-19 J, m_deuterium = 2.012 u, 1 u = 931.5 MeV/c² = 1.6605 × 10^-27 kg)

Radioactive decay: 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?

Radioactive decay: Fermium-253 has a half-life of 3.00 d. A sample of fermium contains 7.37 × nuclei. How long will it take for there to be only 3.36 × fermium nuclei in this sample?

Radioactive decay: A certain substance has a half-life of 5.0 hours. How many nuclei of the substance are required to give an initial activity of 6.0 μCi? 1 Ci = 3.7 × Bq.

Properties of the nucleus: Which of the following statements about the atomic nucleus is correct? (There may be more than one correct choice.)

Nuclear binding energy: The neutral deuterium atom, H, has a mass of 2.014102 u; a neutral 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 H nucleus? (1 u = 931.494 MeV/c²)

Nuclear fission: When a neutron (n) collides with a uranium-235 nucleus it can induce a variety of fission reactions. One such reaction is U + n → Xe + Sr + 2n. How much energy is released in this reaction, given the following mass values: Xe: 139.921620 u Sr : 93.915367 u U: 235.043924 u n: 1.008665 u (1 u = 931.494 MeV/c²)

Nuclear fusion: The primary source of the energy radiated by a star, such as the sun, is

Radioactivity: Which of the following statements about β⁺ decay are correct? (There may be more than one correct choice.) During β⁺ decay

Radioactive decay: A radioisotope has a half-life of τ at a temperature of 150 K. If its temperature is increased to 300 K, what will its half-life be?

Radioactive decay: In a laboratory accident a work area is contaminated with radioactive material. Health physicists monitor the area during a 30-day period and, after correcting for the background rate, obtain the data shown in the table. The accident occurred at t = 0. They determine that it will not be safe for workers to enter the area until the radioactivity level has dropped to 133 counts per minute. Of the choices listed below, which one is the earliest time that workers could safely return

Properties of the nucleus: A certain nucleus containing 8 protons and 7 neutrons has a radius R. Which of the following values would be closest to the expected value of the radius of a nucleus having 51 protons and 69 neutrons?

Biomedicine: A certain isotope has a half-life of 32.4 hr and a relative biological effectiveness of 3.50. A sample of this isotope initially delivers an absorbed dose of 0.240 Gy to 250 g of tissue. (a) What was the initial equivalent dose to the tissue in rem and in sieverts? (b) How many joules of energy did the 250-g sample initially receive from the isotope?

Nuclear binding energy: The carbon in your body was formed in nuclear reactions in long-dead stars. How much energy was released when three ⁴He nuclei combined to make ¹²C? The mass of ⁴He is 4.002603 u, the mass of ¹²C is 12.0000 u, and 1 u = 931.494 MeV/c².

Nuclear binding energy: Radium-226 decays into radon-222 plus an alpha particle. How much energy is released in this process? 1 u = 931.494 MeV/c2, and the relevant mass values are He: 4.002603 u Rn: 222.017570 u Ra: 226.025402 u

Radioactivity: A sphere made of a radioactive isotope initially has a mass of 6.88 kg. The half-life of this isotope is 1.34 h, and it decays by β^- emission. At the end of 2.68 h, what is the mass of this sphere?

Properties of the nucleus: Consider two different isotopes of the same neutral element. Which statements about these isotopes are true? (There may be more than one correct choice.)