Answer at the bottom of the page
21.1 Multiple-Choice Questions
1) All atoms of a given element have the same __________.
A) mass number
B) number of nucleons
C) atomic mass
D) number of neutrons
E) atomic number
2) Atoms containing radioactive nuclei are called __________.
A) radionuclides
B) radioisotopes
C) nucleons
D) nuclides
E) radioisophores
3) What happens to the mass number and the atomic number of an element when it undergoes beta decay?
A) Neither the mass number nor the atomic number change.
B) The mass number decreases by 4 and the atomic number decreases by 2.
C) The mass number does not change and the atomic number increases by 1.
D) The mass number does not change and the atomic number decreases by 2.
E) The mass number increases by 2 and the atomic number increases by 1.
4) Which one of the following is a correct representation of a beta particle?
A) e
B) β
C) e
D) e
E) β
5) Which one of the following is a correct representation of an alpha particle?
A) He
B) H
C) H
D) e
E) H
6) Which one of the following is a correct representation of a positron?
A) e
B) β
C) e
D) e
E) β
7) Which one of the following processes results in an increase in the atomic number?
A) gamma emission
B) positron emission
C) beta emission
D) alpha emission
E) corrosion
8) Of the following processes, which one changes the atomic number?
A) alpha emission
B) beta emission
C) electron capture
D) positron emission
E) All of these processes change the atomic numbers.
9) What radioactive element is used to diagnose medical conditions of the heart and arteries?
A) cobalt-60
B) thallium-201
C) radium-226
D) radon-222
E) thorium-234
10) In what type of radioactive decay does the atomic number of the product increase by one?
A) alpha
B) beta
C) gamma
D) positron emission
E) electron capture
11) Which type of radioactive decay results in no change in mass number and atomic number for the starting nucleus?
A) alpha
B) beta
C) positron emission
D) electron capture
E) gamma
12) Alpha decay produces a new nucleus whose __________ than those respectively of the original nucleus.
A) atomic number is 2 less and mass number is 2 less
B) atomic number is 1 less and mass number is 2 less
C) atomic number is 2 less and mass number is 4 less
D) atomic number is 2 more and mass number is 4 more
E) atomic number is 2 more and mass number is 2 less
13) What is the missing product from this reaction?
P → S + _____
A) He
B) e
C) γ
D) e
E) p
14) What is the atomic number of a neutron?
A) 3
B) 1
C) 2
D) 0
E) 4
15) What happens to the mass number and the atomic number of an element when it emits gamma radiation?
A) The mass number remains unchanged while the atomic number decreases by one.
B) The mass number decreases by four and the atomic number decreases by two.
C) The mass number increases by four and the atomic number increases by two.
D) The mass number remains unchanged while the atomic number increases by one.
E) The mass number and atomic numbers remain unchanged.
16) Atoms with the same atomic number and different mass numbers
A) do not exist.
B) are isomers.
C) are isotopes.
D) are allotropes
E) are resonance structures.
17) How many radioactive decay series exist in nature?
A) 0
B) 1
C) 2
D) 3
E) 10
18) At approximately what number of protons, or neutrons, does the 1:1 ratio of protons to neutrons start to produce unstable nuclei?
A) 10
B) 20
C) 30
D) 50
E) 80
19) Carbon-11 decays by __________.
A) alpha emission
B) beta emission
C) positron emission
D) electron capture
E) neutron capture
20) The formation of krypton from rubidium decay is a result of __________.
A) alpha emission
B) beta emission
C) positron emission
D) electron capture
E) neutron capture
21) The mode of decay of 32P is __________.
A) alpha emission
B) beta emission
C) positron emission
D) electron capture
E) neutron capture
22) The belt of nuclear stability ends with the element __________.
A) lead
B) polonium
C) radon
D) astatine
E) bismuth
23) Which of these nuclides is most likely to be radioactive?
A) K
B) Al
C) I
D) Am
E) Bi
24) What is required for a nuclear transmutation to occur?
A) very high temperature
B) a corrosive environment
C) a particle to collide with a nucleus
D) spontaneous nuclear decay
E) gamma emission
25) In the nuclear transmutation, O (p, α) N, what is the bombarding particle?
A) an alpha particle
B) a beta particle
C) a gamma photon
D) a proton
E) a phosphorus nucleus
26) Cobalt-60 is produced by a three reaction process involving neutron capture, beta-emission, and neutron capture. The initial reactant in the production of cobalt-60 is __________.
A) 59Co
B) 56Fe
C) 58Fe
D) 61Co
E) 60Fe
27) The product of the nuclear reaction in which 28Si is subjected to neutron capture followed by alpha emission is __________.
A) 31S
B) 33S
C) 23Mg
D) 25Mg
E) 25Al
28) Transuranium elements have atomic numbers greater than __________.
A) 90
B) 91
C) 92
D) 93
E) 94
29) What is emitted in the nuclear transmutation, Al(n, ?) Na?
A) an alpha particle
B) a beta particle
C) a neutron
D) a proton
E) a gamma photon
30) In the nuclear transmutation represented by Pu( He, n)?, what is the product?
A) uranium-242
B) curium-245
C) curium-242
D) uranium-245
E) uranium-243
31) In the nuclear transmutation represented by N( n, p)?, what is the emitted particle?
A) neutron
B) proton
C) positron
D) alpha particle
E) electron
32) In the nuclear transmutation represented by N( n, p)?, what is the product?
A) carbon-12
B) carbon-16
C) carbon-14
D) nitrogen-16
E) nitrogen-15
33) Which one of the following requires a particle accelerator to occur?
A) Fe → Co + e
B) Co + n → Co
C) U + n → Np + e
D) Pu + He → Cm + n
E) none of the above
34) Bombardment of uranium-238 with a deuteron (hydrogen-2) generates neptunium-237 and __________ neutrons.
A) 1
B) 2
C) 3
D) 4
E) 5
35) Which of the following correctly represents the transmutation in which neptunium-239 is produced via bombardment of uranium-238 with a neutron?
A) U( n, e) Np
B) U( n, p) Np
C) U( n, γ) Np
D) U( n, α) Np
E) U( n, n) Np
36) Which of the following correctly represents the transmutation in which a curium-242 nucleus is bombarded with an alpha particle to produce a californium-245 nucleus?
A) Cm( He, n) Cf
B) Cm( He, p) Cf
C) Cm( He, e) Cf
D) Cm( n, He) Cf
E) Cm( He, 2 p) Cf
37) Which one of the following can be done to shorten the half-life of the radioactive decay of uranium-238?
A) freeze it
B) heat it
C) convert it to UF6
D) oxidize it to the +2 oxidation state
E) none of the above
38) The beta decay of cesium-137 has a half-life of 30.0 years. How many years must pass to reduce a 25 mg sample of cesium 137 to 8.7 mg?
A) 46
B) 32
C) 3.2
D) 50
E) 52
39) The half-life of 218Po is 3.1 minutes. How much of a 155 gram sample remains after 0.40 hours?
A) 0.00067 g
B) 0.0072 g
C) 0.72 g
D) 0.0047 g
E) none of the above
40) Cesium-131 has a half-life of 9.7 days. What percent of a cesium-131 sample remains after 60 days?
A) 100
B) 0
C) 1.4
D) 98.6
E) more information is needed to solve the problem
41) The half-life for beta decay of strontium-90 is 28.8 years. A milk sample is found to contain 10.3 ppm strontium-90. How many years would pass before the strontium-90 concentration would drop to 1.0 ppm?
A) 92.3
B) 0.112
C) 186
D) 96.9
E) 131
42) The half-life of carbon-11 is 20.3 minutes. How much of a 100.0 mg sample remains after 1.50 hours?
A) 8.48 mg
B) 4.63 mg
C) 12.9 mg
D) 22.6 mg
E) 7.70 mg
43) The half-life of 131I is 0.220 years. How much of a 500.0 mg sample remains after 24 hours?
A) 496 mg
B) 560 mg
C) 219 mg
D) 405 mg
E) 337 mg
44) The half-life of 223Ra is 11.4 days. How much of a 200.0 mg sample remains after 600 hours?
A) 0.219 mg
B) 21.9 mg
C) .0302 mg
D) 43.8 mg
E) 6.04 mg
45) The half-life of 222Rn is 3.80 days. If a sample contains 36.0 g of Rn-222, how many years will it take for the sample to be reduced to 1.00 mg of Rn-222?
A) 19.7
B) 0.1597
C) 8.53
D) 0.0234
E) none of the above
46) The carbon-14 dating method can be used to determine the age of a
A) flint arrowhead.
B) papyrus scroll.
C) stone axe head.
D) clay pot.
E) rock.
47) The basis for the carbon-14 dating method is that
A) the amount of carbon-14 in all objects is the same.
B) carbon-14 is very unstable and is readily lost from the atmosphere.
C) the ratio of carbon-14 to carbon-12 in the atmosphere is a constant.
D) living tissue will not absorb carbon-14 but will absorb carbon-12.
E) All of the above are correct.
48) 210Pb has a half-life of 22.3 years and decays to produce 206Hg . If you start with 7.50 g of 210Pb, how many grams of 206Hg will you have after 17.5 years?
A) 4.35
B) 3.15
C) 3.09
D) 0.0600
E) 1.71
49) The half-life of a radionuclide
A) is constant.
B) gets shorter with passing time.
C) gets longer with passing time.
D) gets shorter with increased temperature.
E) gets longer with increased temperature.
50) The curie is a measure of the
A) number of disintegrations per second of a radioactive substance.
B) total energy absorbed by an object exposed to a radioactive source.
C) lethal threshold for radiation exposure.
D) number of alpha particles emitted by exactly one gram of a radioactive substance.
E) None of the above is correct.
Consider the following data for a particular radionuclide:
51) What is the rate constant (in min-1) for the decay of this radionuclide?
A) 45
B) 32
C) 0.024
D) 0.032
E) 0.022
52) What is the half-life (in min) of this radionuclide?
A) 0.024
B) 0.022
C) 32
D) 0.032
E) 45
53) Cesium-137 undergoes beta decay and has a half-life of 30.0 years. How many beta particles are emitted by a 14.0-g sample of cesium-137 in three minutes?
A) 6.1 × 1013
B) 6.2 × 1022
C) 8.4 × 1015
D) 1.3 × 10-8
E) 8.1 × 1015
54) What is a phosphor?
A) an oxide of phosphorus
B) a substance that thermally reduces to phosphorus
C) a bioluminescent substance
D) a substance that emits light when excited by radiation
E) an alkali metal phosphide
55) Which one of the following devices converts radioactive emissions to light for detection?
A) Geiger counter
B) photographic film
C) scintillation counter
D) none of the above
E) radiotracer
56) Which one of the following is used as a radiotracer to study blood?
A) iron-59
B) technetium-99
C) sodium-23
D) iodine-131
E) phosphorus-32
57) Which one of the following is true?
A) Some spontaneous nuclear reactions are exothermic.
B) Some spontaneous nuclear reactions are endothermic.
C) All spontaneous nuclear reactions are exothermic.
D) There is no relationship between exothermicity and spontaneity in nuclear reactions.
E) All spontaneous nuclear reactions are endothermic.
58) The mass of a proton is 1.673 × 10-24 g. The mass of a neutron is 1.675 × 10-24 g. The mass of the nucleus of an 56Fe atom is 9.289 × 10-23 g. What is the nuclear binding energy (in J) for a 56Fe nucleus? (c = 3.00 × 108 m/s)
A) 2.57 × 10-16
B) 7.72 × 10-8
C) 8.36 × 10-9
D) 7.65 × 10-11
E) 6.07 × 106
59) When two atoms of 2H are fused to form one atom of 4He, the total energy evolved is 3.83 × 10-12 J. What is the total change in mass (in kg) for this reaction? (C = 3.00 × 108 m/s)
A) 1.28 × 10-17
B) 4.26 × 10-26
C) 3.45 × 108
D) 1.15
E) 4.26 × 10-29
60) The mass of a proton is 1.00728 amu and that of a neutron is 1.00867 amu. What is the binding energy (in J) of a Co nucleus? (The mass of a cobalt-60 nucleus is 59.9338 amu.)
A) 2.74 × 10-19
B) 9.12 × 10-28
C) 4.94 × 10-13
D) 8.20 × 10-11
E) 2.74 × 10-16
61) The mass of a proton is 1.00728 amu and that of a neutron is 1.00867 amu. What is the binding energy per nucleon (in J) of a Co nucleus? (The mass of a cobalt-60 nucleus is 59.9338 amu.)
A) 1.37 × 10-12
B) 3.04 × 10-12
C) 2.49 × 10-12
D) 9.43 × 10-13
E) 7.01 × 10-14
62) The mass of a proton is 1.00728 amu and that of a neutron is 1.00867 amu. What is the mass defect (in amu) of a Ni nucleus? (The mass of a nickel-60 nucleus is 59.9308 amu.)
A) 0.5449
B) 1.2374
C) 0.5491
D) 28.7930
E) 1.3066
63) In terms of binding energy per nucleon, what element divides fission and fusion processes?
A) H
B) He
C) C
D) Fe
E) U
64) What type of reaction is known as a thermonuclear reaction?
A) fission
B) fusion
C) transmutation
D) beta emission
E) neutron emission
65) The main scientific difficulty in achieving a controlled fusion process is the
A) enormous repulsion between nuclei being fused.
B) enormous repulsion between the electrons of atoms being fused.
C) very large number of positrons emitted.
D) very large number of x-rays emitted.
E) very large number of gamma rays emitted.
66) What exposure level to radiation is fatal to most humans?
A) 100 rem
B) 200 rem
C) 600 rem
D) 300 rem
E) 1000 rem
67) Which one of the following is not true concerning radon?
A) It decays by alpha emission.
B) It decays to polonium-218, an alpha emitter.
C) It is chemically active in human lungs.
D) It has been implicated in lung cancer.
E) It is generated as uranium decays.
68) Which one of the following forms of radiation can penetrate the deepest into body tissue?
A) alpha
B) beta
C) gamma
D) positron
E) proton
21.2 Bimodal Questions
1) What percentage of electricity generated in the U.S. is from commercial nuclear plants?
A) 1%
B) 10%
C) 19%
D) 50%
E) 90%
2) By what process does thorium-230 decay to radium-226?
A) gamma emission
B) alpha emission
C) beta emission
D) electron capture
E) positron emission
3) The alpha decay of what isotope of what element produces lead-206?
A) polonium-210
4) In balancing the nuclear reaction U → E + He, the identity of element E is __________.
A) Pu
B) Np
C) U
D) Pa
E) Th
5) In balancing the nuclear reaction C → E + e, the identity of element E is __________.
A) B
B) N
C) C
D) O
E) none of the above
6) In balancing the nuclear reaction Br → E + e, the identity of element E is __________.
A) Kr
B) Br
C) U
D) Se
E) none of the above
7) This reaction is an example of __________.
Po → Pb + _____
A) alpha decay
B) beta emission
C) gamma emission
D) positron emission
E) electron capture
8) The missing product from this reaction is __________.
I → Te + _____
A) He
B) e
C) n
D) e
E) γ
9) The missing product from this reaction is __________.
Cl + _____ → Ar + e
A) He
B) e
C) n
D) e
E) γ
10) The missing product from this reaction is __________.
Al + n → Si + _____
A) He
B) e
C) n
D) e
E) γ
11) The missing product from this reaction is __________.
B + _____ → N + n
A) He
B) e
C) n
D) e
E) γ
12) The missing product from this reaction is __________.
Fr → N + _____
A) He
B) e
C) n
D) e
E) γ
13) The missing product from this reaction is __________.
I → _____ + e
A) Te
B) Xe
C) Te
D) e
E) none of the above
14) The missing product from this reaction is __________.
Na → _____ + e
A) Na
B) Mg
C) Mg
D) Ne
E) none of the above
15) The missing product from this reaction is __________.
Se + e → _____
A) Se
B) As
C) Se
D) Br
E) none of the above
16) The missing product from this reaction is __________.
Np → Pa + _____
A) He
B) e
C) n
D) e
E) γ
17) This reaction is an example of __________.
Ca → K + _____
A) alpha decay
B) beta decay
C) positron decay
D) electron capture
E) gamma emission
18) This reaction is an example of __________.
Kr → Rb + _____
A) alpha decay
B) beta decay
C) positron decay
D) electron capture
E) gamma emission
19) This reaction is an example of __________.
P → Si + _____
A) alpha decay
B) beta decay
C) positron decay
D) electron capture
E) gamma emission
20) This reaction is an example of __________.
P + _____ → Si
A) alpha decay
B) beta decay
C) positron decay
D) electron capture
E) gamma emission
21) The missing product in this reaction would be found in which group of the periodic table?
Na → e + _____
A) 1A
B) 2A
C) 3A
D) 8A
E) 7A
22) The missing product in this reaction combines with oxygen to form a compound with the formula __________.
K → e + _____
A) M2O
B) MO
C) MO2
D) M2O3
E) M2O2
23) Radium undergoes alpha decay. The product of this reaction also undergoes alpha decay. What is the product of this second decay reaction?
A) Po
B) Rn
C) U
D) Th
E) Hg
24) 41Ca decays by electron capture. The product of this reaction undergoes alpha decay. What is the product of this second decay reaction?
A) Ti
B) Ca
C) Ar
D) Cl
E) Sc
25) What is the mass number of a neutron?
A) 2
B) 1
C) 3
D) 4
E) 0
26) Nuclei above the belt of stability can lower their neutron-to-proton ratio by __________.
A) beta emission
B) gamma emission
C) positron emission
D) electron capture
E) Any of the above processes will lower the neutron-to-proton ratio.
27) What is the largest number of protons that can exist in a nucleus and still be stable?
A) 206
B) 50
C) 92
D) 83
E) 84
28) The three radioactive series that occur in nature end with what element?
A) Bi
B) U
C) Po
D) Pb
E) Hg
29) The largest number of stable nuclei have an __________ number of protons and an __________ number of neutrons.
A) even, even
B) odd, odd
C) even, odd
D) odd, even
E) even, equal
30) In the nuclear transmutation represented by O(p, α) N, the emitted particle is __________.
A) a beta particle.
B) an alpha particle.
C) a proton.
D) a positron.
E) a neutron.
31) Bombardment of uranium-235 with a neutron generates tellurium-135, 3 neutrons, and __________.
A) zirconium-98.
B) krypton-101.
C) krypton-103.
D) strontium-99.
E) zirconium-99.
32) The reaction shown below is responsible for creating 14C in the atmosphere. What is the bombarding particle?
N + _____ → C + H
A) alpha particle
B) electron
C) neutron
D) positron
E) proton
33) How many neutrons are emitted when a californium-249 nucleus (Z=98) is bombarded with a carbon-12 nucleus to produce a Rf nucleus?
A) one
B) three
C) two
D) four
E) zero
34) How many neutrons are emitted when a californium-249 nucleus (Z=98) is bombarded with a nitrogen-15 nucleus to produce a Db nucleus?
A) two
B) three
C) four
D) one
E) zero
35) What order process is radioactive decay?
A) zeroth
B) first
C) second
D) third
E) fourth
36) Due to the nature of the positron, __________ is actually detected in positron emission tomography.
A) alpha radiation
B) beta radiation
C) gamma radiation
D) x-ray emission
E) neutron emission
37) The mass of a proton is 1.00728 amu and that of a neutron is 1.00867 amu. What is the mass defect (in amu) of a Co nucleus? (The mass of a cobalt-60 nucleus is 59.9338 amu.)
A) 27.7830
B) 0.5489
C) 0.5405
D) 0.0662
E) 0.4827
38) What is the typical percent of uranium-235 in the enriched UO2 pellets used in nuclear reactors?
A) 0.7
B) 1
C) 3
D) 10
E) 14
39) On average, __________ neutrons are produced by every fission of a uranium-235 nucleus.
A) 4
B) 3.5
C) 1
D) 2.4
E) 2
40) What drives the turbine in a nuclear power plant?
A) the moderator
B) steam
C) the control rods
D) the primary coolant
E) UF6 gas
41) Who is credited with first achieving fission of uranium-235?
A) Fermi
B) Rutherford
C) Curie
D) Dalton
E) Faraday
42) When ionizing radiation enters the body, what is the predominant free radical produced?
A) H
B) H3O
C) protein
D) OH
E) H2O
43) The nuclear disintegration series of __________ is the source of radon-222 in soil.
A) 235U
B) 238U
C) 236Pb
D) 235Th
E) 14C
21.3 Algorithmic Questions
1) The half-life of cobalt-60 is 5.20 yr. How many milligrams of a 2.000-mg sample remains after 6.55 years?
A) 0.837
B) 3.23 × 10-15
C) 4.779
D) 1.588
E) 1.163
2) Strontium-90 is a byproduct in nuclear reactors fueled by the radioisotope uranium-235. The half-life of strontium-90 is 28.8 yr. What percentage of a strontium-90 sample remains after 75.0 yr?
A) 68.1
B) 16.5
C) 7.40
D) 38.4
E) 2.60
3) Carbon-11 is used in medical imaging. The half-life of this radioisotope is 20.4 min. What percentage of a sample remains after 60.0 min?
A) 71.2
B) 5.28
C) 13.0
D) 34.0
E) 2.94
4) A rock contains 0.275 mg of lead-206 for each milligram of uranium-238. The half-life for the decay of uranium-238 to lead-206 is 4.5 × 109 yr. The rock was formed __________ yr ago.
A) 1.42 × 109
B) 9.62 × 108
C) 1.24 × 109
D) 1.79 × 109
E) 1.39 × 109
5) 131I has a half-life of 8.04 days. Assuming you start with a 3.53 mg sample of 131I, how many mg will remain after 13.0 days?
A) 0.326
B) 0.268
C) 0.422
D) 2.30
E) 1.15
6) The decay of a radionuclide with a half-life of 2.3 × 105 years has a rate constant (in yr-1) equal to __________.
A) 3.3 × 105
B) 3.0 × 10-6
C) 6.0 × 10-6
D) 2.8 × 103
E) 5.9 × 10-8
7) Potassium-40 decays to argon-40 with a half-life of 1.27 × 109 yr. The age of a mineral sample that has a mass ratio of 40Ar to 40K of 0.712 is __________ yr.
A) 1.78 × 109
B) 1.11 × 109
C) 1.61 × 109
D) 6.83 × 108
E) 9.85 × 108
8) If we start with 1.000 g of strontium-90, 0.908 g will remain after 4.00 yr. This means that the half-life of strontium-90 is __________ yr.
A) 3.05
B) 4.40
C) 28.8
D) 3.63
E) 41.6
9) If we start with 1.000 g of cobalt-60, 0.675 g will remain after 3.00 yr. This means that the half-life of cobalt-60 is __________ yr.
A) 3.08
B) 4.44
C) 2.03
D) 5.30
E) 7.65
10) A freshly prepared sample of curium-243 undergoes 3312 disintegrations per second. After 6.00 yr, the activity of the sample declines to 2755 disintegrations per second. The half-life of curium-243 is __________ yr.
A) 4.99
B) 32.6
C) 7.21
D) 0.765
E) 22.6
11) Carbon-11 decays by positron emission:
C → B + e
The decay occurs with a release of 2.87 × 1011 J per mole of carbon-11. When 4.00 g of carbon-11 undergoes this radioactive decay, __________ g of mass is converted to energy.
A) 1.16 × 10-3
B) 3.48 × 105
C) 1.16 × 10-6
D) 8.62 × 102
E) 1.28 × 10-2
12) How much energy (in J) is produced when 0.082 g of matter is converted to energy?
A) 7.4 × 1018
B) 7.4 × 1012
C) 2.5 × 104
D) 7.4 × 1015
E) 2.5 × 107
21.4 Short Answer Questions
1) What happens in the nucleus of an atom that undergoes positron emission?
2) What is the predominant isotope of uranium?
3) What happens to the atomic mass number and the atomic number of a radioisotope when it undergoes alpha emission?
4) High speed electrons emitted by an unstable nucleus are called __________.
5) e represents __________.
6) What isotope of what element is produced if krypton-81 undergoes beta decay?
7) Stable nuclei with low atomic numbers, up to 20, have a neutron to proton ratio of approximately __________.
8) The first nuclear transmutation resulted in the conversion of nitrogen-14 to __________.
9) Conversion of one nucleus into another was first demonstrated in 1919 by __________.
10) The initial element used to make cobalt-60 for cancer radiation therapy is __________.
11) The half-life for the beta decay of potassium-40 is 1.3 × 109 years. What is the rate constant for this decay?
1.3 × 109 years = 0.693/k
k = 5.3 × 10-10 year-1
12) __________ discovered radioactivity.
13) Carbon-11, fluorine-18, oxygen-15 and nitrogen-13 are all used in the clinical diagnostic technique known as __________.
14) What is the source of the tremendous energies produced by nuclear reactions?
15) Control rods in a nuclear reactor are composed of boron and __________.
16) The amount of fissionable material necessary to maintain a chain reactions is called the __________.
17) What was the purpose of the Manhattan project?
18) When living tissue is irradiated most of the energy is absorbed by __________.
19) The relative biological effectiveness (RBE) values of beta rays, gamma rays, and alpha rays are, respectively
20) The major type of cancer caused by radiation is __________.
21) Radioactive seeds that are implanted into a tumor are coated with __________ to stop alpha and beta ray penetration.
21.5 True/False Questions
1) Gamma radiation only changes the atomic number but not the mass number of a nucleus.
2) Positron emission causes a decrease of one in the atomic number.
3) The neutron/proton ratio of stable nuclei increases with increasing atomic number.
4) Charged particles are accelerated because the faster they move there is a greater chance of producing a nuclear reaction.
5) Radioactive decay is a first order kinetic process.
6) In radioactive dating the ratio of carbon-12 to carbon-14 is related to the time of death of the animal or plant under investigation.
7) In the formula k=0.693/t1/2, k is the decay constant.
8) The energy produced by the sun is the result of nuclear fusion.
9) The SI unit of an absorbed dose of radiation is the gray.
10) The relative biological effectiveness (RBE) is 10 fold greater for gamma radiation than for alpha radiation.
21.6 Essay Questions
1) Electrons do not exist in the nucleus, yet beta emission is ejection of electrons from the nucleus. How does this happen?
2) List the common particles and their symbols used in descriptions of radioactive decay and nuclear transformations.
3) When an isotope undergoes electron capture, what happens to the captured electron?
4) The use of radioisotopes in tracing metabolism is possible because __________.
Answer:
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