Quiz 42: Nuclear Physics
Physics & Astronomy
Q 1Q 1
Consider two different isotopes of the same neutral element. Which statements about these isotopes are true? (There may be more than one correct choice.)
A) Both isotopes contain the same number of neutrons.
B) Both isotopes contain the same number of protons.
C) Both isotopes contain the same number of nucleons.
D) Both isotopes contain the same number of orbital electrons.
E) The sum of the protons and neutrons is the same for both isotopes.
Free
Multiple Choice
B, D
Q 2Q 2
Consider the short-lived neutral isotope represented by X. Which of the following statements about this isotope are correct? (There may be more than one correct choice.)
A) The isotope has 25 nucleons.
B) The isotope has 25 protons.
C) The isotope has 25 neutrons.
D) The isotope has 15 orbital electrons.
E) The isotope has 15 protons.
F) The isotope has 10 neutrons.
Free
Multiple Choice
A, D, E, F
Q 3Q 3
Which of the following statements about the atomic nucleus is correct? (There may be more than one correct choice.)
A) Large nuclei are denser than light nuclei.
B) All nuclei have nearly the same density.
C) The nucleus is held together more by the electrical force than by the gravitational force.
D) A nucleus containing 20 nucleons will have approximately twice the radius as a nucleus containing 10 nucleons.
E) As the number of nucleons increases the binding energy per nucleon always increases.
Free
Multiple Choice
B
Q 4Q 4
For a Nb atom, the number of protons, neutrons, and electrons in the atom is
A) 41, 52, 93.
B) 41, 52, 52.
C) 41, 52, 41.
D) 41, 52, 0.
E) 52, 41, 0.
Free
Multiple Choice
Free
True False
Q 6Q 6
Going from medium mass nuclei to heavy nuclei, the average binding energy per nucleon
A) decreases.
B) behaves randomly with no clear pattern.
C) does not change.
D) increases.
E) doubles.
Free
Multiple Choice
Q 7Q 7
Heavier stable nuclei tend to have
A) half as many protons as neutrons.
B) the same number of neutrons and protons.
C) more neutrons than protons.
D) no clear trend in the relative number of neutrons and protons.
E) more protons than neutrons.
Free
Multiple Choice
Q 8Q 8
Which of the following statements about the strong nuclear force are correct? (There may be more than one correct choice.)
A) It acts equally on protons and neutrons but not on electrons.
B) It acts equally on protons, neutrons, and electrons.
C) It has a much longer range than the electric force.
D) It keeps electrons in their orbits around the nucleus.
E) Because of its very short range, there is a limit to how large the nucleus can be.
Free
Multiple Choice
Q 9Q 9
If a nucleus decays by β- decay to a daughter nucleus, which of the following statements about this decay are correct? (There may be more than one correct choice.)
A) The daughter nucleus has more protons than the original nucleus.
B) The daughter nucleus has more neutrons than the original nucleus.
C) The daughter nucleus has the same number of nucleons as the original nucleus.
D) The daughter nucleus has fewer protons than the original nucleus.
E) The daughter nucleus has fewer neutrons than the original nucleus.
Free
Multiple Choice
Q 10Q 10
If a nucleus decays by alpha decay to a daughter nucleus, which of the following statements about this decay are correct? (There may be more than one correct choice.)
A) The daughter nucleus has more protons than the original nucleus.
B) The daughter nucleus has more neutrons than the original nucleus.
C) The daughter nucleus has the same number of nucleons as the original nucleus.
D) The daughter nucleus has fewer protons than the original nucleus.
E) The daughter nucleus has fewer neutrons than the original nucleus.
Free
Multiple Choice
Q 11Q 11
If a nucleus decays by gamma decay to a daughter nucleus, which of the following statements about this decay are correct? (There may be more than one correct choice.)
A) The daughter nucleus has more protons than the original nucleus.
B) The daughter nucleus has more neutrons than the original nucleus.
C) The daughter nucleus has the same number of nucleons as the original nucleus.
D) The daughter nucleus has fewer protons than the original nucleus.
E) The daughter nucleus has fewer neutrons than the original nucleus.
Free
Multiple Choice
Q 12Q 12
If a nucleus decays by β+ decay to a daughter nucleus, which of the following statements about this decay are correct? (There may be more than one correct choice.)
A) The daughter nucleus has more protons than the original nucleus.
B) The daughter nucleus has more neutrons than the original nucleus.
C) The daughter nucleus has the same number of nucleons as the original nucleus.
D) The daughter nucleus has fewer protons than the original nucleus.
E) The daughter nucleus has fewer neutrons than the original nucleus.
Free
Multiple Choice
Q 13Q 13
Which of the following statements about β+ decay are correct? (There may be more than one correct choice.) During β+ decay
A) an orbital electron is captured by the nucleus.
B) a proton is emitted from the nucleus.
C) a neutron in the nucleus decays to a proton and an electron.
D) a proton in the nucleus decays to a positron and a neutron.
E) the atomic number Z of the isotope increases by one unit but the atomic weight A remains unchanged.
Free
Multiple Choice
Q 14Q 14
A radioactive isotope decays by β- emission with a half-life of 1.0 min. During the first 1.0 min, a particular sample emits 1000 β- particles. During the next 1.0 min, the number of β- particles this sample will emit will be closest to
A) 250.
B) 500.
C) 1000.
D) 1500.
E) 2000.
Free
Multiple Choice
Q 15Q 15
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?
A) 4τ
B) 2 τ
C) τ
D) τ/2
E) τ/4
Free
Multiple Choice
Q 16Q 16
The decay rate of an isotope is initially R0, but after one half-life has gone by, the rate is R0/2. At the end of the NEXT half-life, what will the decay rate be?
A) 0
B) R0/16
C) R0/e
D) R0/4
E) R0/e2
Free
Multiple Choice
Q 17Q 17
The half-life of cobalt-60 is 5.3 years, while that of strontium-90 is 28 years. Suppose you have a sample of each, such that they initially contain equal numbers of atoms of these nuclides. How will the activities (number of decays per second) of the samples compare?
A) The activity of the cobalt-60 sample will be greater.
B) The activities cannot be compared without more information.
C) The activities will be equal.
D) The activity of the strontium-90 sample will be greater.
Free
Multiple Choice
Q 18Q 18
The half-life of cobalt-60 is 5.3 years, while that of strontium-90 is 28 years. Suppose that samples of cobalt-60 and strontium-90 are such that they initially have the same activity (number of decays per second). What is true about the initial numbers of cobalt-60 and strontium-90 nuclei in these samples?
A) There are more strontium-90 than cobalt-60 nuclei.
B) There are equal numbers of cobalt-60 and strontium-90 nuclei.
C) There are more cobalt-60 than strontium-90 nuclei.
D) It is not possible to compare numbers of nuclei without knowing the masses of the samples.
Free
Multiple Choice
Q 19Q 19
A radioactive nuclide of atomic number Z emits an electron, then the daughter nuclide emits a gamma ray. What is the atomic number of the resulting nuclide after both processes?
A) Z + 1
B) Z - 1
C) Z - 2
D) Z - 3
E) Z + 2
Free
Multiple Choice
Q 20Q 20
Modern nuclear bomb tests have created an extra high level of 14C in our atmosphere. Suppose that future archaeologists date samples from our era, but do not know about this testing. Will their dates be too young, too old, or still correct? If correct they are correct, why?
A) too young
B) too old
C) correct, because 14C from bomb tests is different from that produced naturally
D) correct, because modern biological materials do not gather 14C from bomb tests
Free
Multiple Choice
Q 21Q 21
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?
A) 1.85R
B) 2.00R
C) 2.14R
D) 6.38R
E) 8.00R
Free
Multiple Choice
Q 22Q 22
A certain nucleus containing 8 protons and 7 neutrons has a density ρ. Which of the following values would be closest to the expected value of the density of a nucleus having 51 protons and 69 neutrons?
A) 1.00 ρ
B) 1.85 ρ
C) 2.00 ρ
D) 2.14 ρ
E) 8.00 ρ
Free
Multiple Choice
Q 23Q 23
What would be the expected radius of a nucleus having 82 protons and 125 neutrons?
A) 5.2 fm
B) 5.9 fm
C) 6.0 fm
D) 7.1 fm
E) 17 fm
Free
Multiple Choice
Q 24Q 24
What would be the expected radius of the nucleus of Sr?
A) 4.0 fm
B) 1.2 fm
C) 5.4 fm
D) 0.11 pm
E) 0.54 pm
Free
Multiple Choice
Q 25Q 25
If a nucleus had a diameter of 8.0 fm, what would be its expected mass, in atomic mass units?
A) 7 u
B) 296 u
C) 37 u
D) 64 u
E) 128 u
Free
Multiple Choice
Q 26Q 26
Two identical nuclei of mass 18 u are made to unite to make a single nucleus of mass 36 u. What is the radius of the result of this fusion?
A) 4.0 fm
B) 6.3 fm
C) 4.5 fm
D) 7.2 fm
Free
Multiple Choice
Q 27Q 27
The following masses are known: n (neutron) 1.008665 u
H 1.007825 u
Fe 56.935399 u
What is the binding energy of
Fe, in MeV? (1 u = 1.6605 × 10-27 kg = 931.5 MeV/c2)
A) 500 MeV
B) 550 MeV
C) 610 MeV
D) 660 MeV
E) 710 MeV
Free
Multiple Choice
Q 28Q 28
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)
A) 1.1 MeV
B) 1.7 MeV
C) 2.2 MeV
D) 2.9 MeV
E) 3.4 MeV
Free
Multiple Choice
Q 29Q 29
What is the binding energy per nucleon for Al? The neutral
Al atom has a mass of 26.981539 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. (1 u = 931.494 MeV/c2)
A) 8.3 MeV
B) 6.7 MeV
C) 5.4 MeV
D) 3.4 MeV
E) 2.8 MeV
Free
Multiple Choice
Q 30Q 30
Uranium-238 decays into thorium-234 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
Th: 234.043583 u
U: 238.050786 u
A) 4.28 MeV
B) 3.76 MeV
C) 3.18 MeV
D) 2.89 MeV
E) 5.05 MeV
Free
Multiple Choice
Q 31Q 31
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
A) 4.24 MeV
B) 3.76 MeV
C) 4.87 MeV
D) 5.05 MeV
E) 5.39 MeV
Free
Multiple Choice
Q 32Q 32
Plutonium-239 decays into uranium-235 plus an alpha particle. The energy released in the process is 5.24 MeV. Given the following mass values He: 4.002603 u
U: 235.043924 u
What is the mass of
Pu in atomic mass units? (1 u = 931.494 MeV/c2)
A) 239.05215 u
B) 239.02775 u
C) 239.00189 u
D) 238.99919 u
E) 238.98884 u
Free
Multiple Choice
Q 33Q 33
A stationary plutonium-239 nucleus decays into a uranium-235 nucleus plus an alpha particle. The energy released in the process is 5.24 MeV. Given the following mass values He: 4.002603 u
U: 235.043924 u
What is the kinetic energy of the
U nucleus? (1 u =931.494 MeV/c2)
A) 0.0829 MeV
B) 0.0837 MeV
C) 0.0852 MeV
D) 0.0863 MeV
E) 0.0877 MeV
Free
Multiple Choice
Q 34Q 34
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.
A) 7.274 MeV
B) 3716 MeV
C) 8.424 MeV
D) 2.106 MeV
Free
Multiple Choice
Q 35Q 35
How much energy is released when 1.40 μg of 3H have decayed to 3He? The mass of 3He is 3.016029 u, the mass of 3H is 3.016049 u, and 1 u = 931.494 MeV/c2.
A) 830 J
B) 11,900 J
C) 7970 J
D) 71,700 J
E) 23,900 J
Free
Multiple Choice
Q 36Q 36
The set of nuclear reactions that power our sun can be summarized a 4p+ → 4He+2 + 2e+. The masses of the particles involved are 938.272 MeV/c2 (proton, p+), 3727.38 MeV/c2 (alpha particle, 4He+2), and 0.511 MeV/c2 (positron, e+). How much energy is released by each set of these reactions?
A) 24.69 MeV
B) 28.3 MeV
C) 2790 MeV
D) 279 MeV
Free
Multiple Choice
Q 37Q 37
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?
A) 6.88 kg
B) 3.44 kg
C) 1.72 kg
D) 2.53 kg
Free
Multiple Choice
Q 38Q 38
A radioactive atom has 98 protons and 249 nucleons. If it undergoes alpha decay, what are the number of protons and nucleons, respectively, in the daughter nucleus?
A) 100, 245
B) 94, 247
C) 96, 245
D) 96, 247
E) 100, 249
Free
Multiple Choice
Q 39Q 39
Scandium, Sc, decays by emitting a positron. What is the nuclide that is the product of the decay?
A) Sc
B) Sc
C) Ca
D) Ca
E) Sc
Free
Multiple Choice
Q 40Q 40
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
A) not subject to alpha, β+, or β- decay.
B) subject to alpha decay only.
C) subject to β+ decay only.
D) subject to β- decay only.
E) subject to β+ or β- decay, but not to alpha decay.
Free
Multiple Choice
Q 41Q 41
The stability of Sc 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
K: 42.960717 u
Ca: 46.954543 u
Sc 46.952409 u
Ti: 46.951764 u
The
Sc nuclide is
A) not subject to alpha, β+, or β- decay.
B) subject to alpha decay only.
C) subject to β+ decay only.
D) subject to β- decay only.
E) subject to β+ or β- decay, but not to alpha decay.
Free
Multiple Choice
Q 42Q 42
The stability of Fe 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
Cr: 51.944768 u
Mn: 55.938907 u
Fe: 55.934939 u
Co: 55.939841 u
The
Fe nuclide is
A) not subject to alpha, β+, or β- decay.
B) subject to alpha decay only.
C) subject to β+decay only.
D) subject to β- decay only.
E) subject to β+ or β- decay, but not to alpha decay.
Free
Multiple Choice
Q 43Q 43
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 × 1010 Bq.
A) 5.8 × 109
B) 8.5 × 108
C) 6.3 × 108
D) 3.2 × 109
E) 2.4 × 109
Free
Multiple Choice
Q 44Q 44
What mass of 14C (having a half-life of 5730 years) do you need to provide a decay rate of
280.0 Bq? (1 u = 1.6605 × 10-27 kg)
A) 1.70 × 10-12 kg
B) 5.38 × 10-19 kg
C) 3.84 × 10-20 kg
D) 8.68 × 10-13 kg
Free
Multiple Choice
Q 45Q 45
How many days are required for a radioactive sample, with a half-life of 5.7 d and an initial activity of 1.07 × 105 Bq, to decay to an activity of 100 Bq?
A) 57 d
B) 46 d
C) 68 d
D) 39 d
Free
Multiple Choice
Q 46Q 46
A hospital patient has been given some 131I (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.
A) 17 d
B) 12 d
C) 8.0 d
D) 7.2 d
Free
Multiple Choice
Q 47Q 47
The material used in certain nuclear bombs is 239Pu, which has a half-life of about 20,000 years. How long must we wait for a buried stockpile of this substance to decay to 4.0% of its original 239Pu mass?
A) 93,000 y
B) 64,000 y
C) 45,000 y
D) 800 y
Free
Multiple Choice
Q 48Q 48
An air sample is contaminated with 15O, which has a half-life of 2.03 min. One possible way to minimize its hazard is to pass it through a long pipe to allow it to decay inside the pipe until it can be safely released into the atmosphere. If the oxygen moves at a speed of 1.1 m/s in the pipe, how long must the pipe be for the sample to have decayed to 3.0% of its original activity just as it leaves the pipe?
A) 680 m
B) 8.0 m
C) 7.0 m
D) 2.0 m
Free
Multiple Choice
Q 49Q 49
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?
A) 1.02 min
B) 1.62 min
C) 0.632 min
D) 2.70 min
E) 3.24 min
Free
Multiple Choice
Q 50Q 50
A radioactive sample has a half-life of 10 min. What fraction of the sample is left after 40 min?
A) 1/2
B) 1/4
C) 1/8
D) 1/16
E) 1/32
Free
Multiple Choice
Q 51Q 51
Fermium-253 has a half-life of 3.00 d. A sample of fermium contains 7.37 × 107 nuclei. How long will it take for there to be only 3.36 × 106 fermium nuclei in this sample?
A) 2.75 d
B) 9.80 d
C) 13.4 d
D) 15.7 d
E) 58.6 d
Free
Multiple Choice
Q 52Q 52
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?
A) 38 days
B) 44 days
C) 50 days
D) 32 days
E) 24 days
Free
Multiple Choice
Q 53Q 53
The unstable isotope 234Th decays by β emission with a half-life of 24.5 days. The initial decay rate of the sample was 9.9 × 1013 Bq. (1 u = 1.6605 x 10-27 kg)
(a) What mass of 234Th was initially present?
(b) What is the decay rate after 68 days?
Free
Essay
Q 54Q 54
An isotope of Tc having a half-life of 6.0 h is used in bone scans. If a certain amount of this Tc is injected into the body, how long does it take for its initial decay rate to decrease BY 99%?
A) 0.060 h
B) 3.3 h
C) 33 h
D) 40 h
E) slightly more than a month
Free
Multiple Choice
Q 55Q 55
The radioactivity due to carbon-14 measured in a piece of a wood from an ancient site was found to produce 20 counts per minute from a given sample, whereas the same amount of carbon from a piece of living wood produced 160 counts per minute. The half-life of carbon-14, a beta emitter, is 5730 y. The age of the artifact is closest to
A) 5700 y
B) 12,000 y
C) 15,000 y
D) 17,000 y
E) 23,000 y
Free
Multiple Choice
Q 56Q 56
Carbon-14 has a half-life of 5730 y. 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, 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. How old is the sample of wood?
A) 3870 y
B) 4250 y
C) 4590 y
D) 2630 y
E) 2940 y
Free
Multiple Choice
Q 57Q 57
Living matter has 1.3 × 10-10 % of its carbon in the form of 14C which has a half-life of 5730 y. A mammoth bone has a 300-g sample of carbon separated from it, and the sample is found to have an activity of 20 decays per second. How old is the bone?
A) 15,000 y
B) 10,900 y
C) 11,500 y
D) 7600 y
E) 6400 y
Free
Multiple Choice
Q 58Q 58
An archaeologist finds the 14C in a sample of 3.10 g of material to be decaying at 107 counts per second. A modern 1.00-g sample of the same material decays at 151 counts per second. The half-life of 14C is 5730 y. How old is the sample?
A) 12,200 y
B) 8460 y
C) 25,100 y
D) 12,600 y
Free
Multiple Choice
Q 59Q 59
An ancient rock is found to contain 40Ar gas, indicating that 77% of the 40K in the rock has decayed since the rock solidified. Any argon would have boiled out of liquid rock. The half-life of 40K is 1.25 billion years. How long ago did the rock solidify?
A) 2.6 billion years
B) 0.50 billion years
C) 1.8 billion years
D) 0.30 billion years
Free
Multiple Choice
Q 60Q 60
Today, the uranium found on Earth contains 0.720% 235U (with a half-life of 0.700 billion years) and 99.28% 238U (with a half-life of 4.50 billion years). At a time 2.20 billion years ago, what percent of the uranium on Earth was 238U (assuming that no other uranium isotopes were present)?
A) 95.6%
B) 2.18%
C) 6.29%
D) 8.68%
E) 4.53%
Free
Multiple Choice
Q 61Q 61
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?
Free
Essay
Q 62Q 62
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?
A) 0.23
B) 0.25
C) 0.28
D) 0.30
E) 0.32
Free
Multiple Choice
Q 63Q 63
A 70-kg laboratory technician absorbs 2.9 mJ of 0.50-MeV gamma rays in a workday. How many gamma-ray photons does the technician absorb in a workday?
A) 3.6 × 1010
B) 3.6 × 109
C) 3.6 × 108
D) 1.0 × 109
E) 1.0 × 108
Free
Multiple Choice
Q 64Q 64
A 57-kg researcher absorbs 6.3 × 108 neutrons in a workday. The energy of the neutrons is 2.6 MeV. The relative biological efficiency (RBE) for fast neutrons is 10. What is the equivalent dosage of the radiation exposure, in mrem, of this worker?
A) 4.6 mrem
B) 1.4 mrem
C) 2.9 mrem
D) 14 mrem
E) 46 mrem
Free
Multiple Choice
Q 65Q 65
The radioactive nuclei 60Co is widely used in medical applications. It undergoes beta decay, and the total energy of the decay process is 2.82 MeV per decay event. The half-life of this nucleus is 272 days. Suppose that a patient is given a dose of 6.9 µCi of 60Co. If all of this material decayed while in the patient's body, what would be the total energy deposited there? (1 Ci = 3.70 × 1010 decays/s)
A) 11 J
B) 8.6 GJ
C) 3.9 J
D) 24 J
E) 4.15 MJ
Free
Multiple Choice