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College Physics for AP® Courses 2e

Test Prep for AP® Courses

College Physics for AP® Courses 2eTest Prep for AP® Courses

32.2 Biological Effects of Ionizing Radiation


A patient receives A rad of radiation as part of her treatment and absorbs E J of energy. The RBE of the radiation particles is R. If the RBE is increased to 1.5R, what will be the energy absorbed by the patient?

  1. 1.5E J
  2. E J
  3. 0.75E J
  4. 0.67E J

If a 90-kg person is exposed to 50 mrem of alpha particles (with RBE of 16), calculate the dosage (in rad) received by the person. What is the amount of energy absorbed by the person?

32.5 Fusion

The figure is a graph with an arrow pointing up for the y-, vertical axis and labeled PEtot. The x-, horizontal axis is labeled with arrow r. A red line indicating the plot starts horizontally below the x-axis and then quickly rises toward the horizontal line marked 0 and is labeled Attractive nuclear below the 0 line. There is a light nuclei dot on the slope of the line above the x-axis with an arrow pointing down to the left along the slope and is labeled Pulled together. After the plot reaches a maximum, the red line of the plot moves down and at less of slope. This portion of the plot is labeled Repulsive Coulomb. On this portion is another light nuclei dot labeled Repelled with a line pointing down and to the right along the slope of the plot.
Figure 32.31

This figure shows a graph of the potential energy between two light nuclei as a function of the distance between them. Fusion can occur between the nuclei if the distance is

  1. large so that kinetic energy is low.
  2. large so that potential energy is low.
  3. small so that nuclear attractive force can overcome Coulomb’s repulsion.
  4. small so that nuclear attractive force cannot overcome Coulomb’s repulsion.

In a nuclear fusion reaction, 2 g of hydrogen is converted into 1.985 g of helium. What is the energy released?

  1. 4.5 × 103 J
  2. 4.5 × 106 J
  3. 1.35 × 1012 J
  4. 1.35 × 1015 J

When deuterium and tritium nuclei fuse to produce helium, what else is produced?

  1. positron
  2. proton
  3. α-particle
  4. neutron

Suppose two deuterium nuclei are fused to produce helium.

  1. Write the equation for the fusion reaction.
  2. Calculate the difference between the masses of reactants and products.
  3. Using the result calculated in (b), find the energy produced in the fusion reaction.

Assume that the mass of deuterium is 2.014102 u, the mass of helium is 4.002603 u and 1 u = 1.66 × 10-27 kg.

32.6 Fission


Which of the following statements about nuclear fission is true?

  1. No new elements can be produced in a fission reaction.
  2. Energy released in fission reactions is generally less than that from fusion reactions.
  3. In a fission reaction, two light nuclei are combined into a heavier one.
  4. Fission reactions can be explained on the basis of the conservation of mass-energy.

What is the energy obtained when 10 g of mass is converted to energy with an efficiency of 70%?

  1. 3.93 × 1027 MeV
  2. 3.93 × 1030 MeV
  3. 5.23 × 1027 MeV
  4. 5.23 × 1030 MeV

In a neutron-induced fission reaction of 239Pu, which of the following is produced along with 96Sr and four neutrons?

  1. 56 139 Ba 56 139 Ba
  2. 56 140 Ba 56 140 Ba
  3. 54 139 Xe 54 139 Xe
  4. 54 140 Xe 54 140 Xe

When 235U is bombarded with one neutron, the following fission reaction occurs: 92 235 U+n 56 141 Ba+ y 92 Kr+xn 92 235 U+n 56 141 Ba+ y 92 Kr+xn .

  1. Find the values for x and y.
  2. Assuming that the mass of 235U is 235.04 u, the mass of 141Ba is 140.91 u, the mass of 92Kr is 91.93 u, and the mass of n is 1.01 u, a student calculates the energy released in the fission reaction as 2.689 × 10−8, but forgets to write the unit. Find the correct unit and convert the answer to MeV.
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