What particle is emitted when 20Na decays to 20Ne? (The atomic numbers of Na and Ne are, respectively, 11 and 10.)
a. beta (positron)
c. alpha
b. gamma quantum
d. beta (electron)
[Ques. 2] A radioactive isotope that emits an alpha particle will change in what respect?
a. Atomic number decreases by four.
b. Both choices a and b are valid. c. Mass number decreases by four.
d. None of these choices are valid.
[Ques. 3] A radioactive isotope that emits a gamma quantum will change in what respect?
a. Atomic number increases by one.
b. Atomic mass number decreases by one.
c. Atomic number decreases by one.
d. None of these choices are valid.
[Ques. 4] The alpha emission process results in the daughter nucleus differing in what manner from the parent?
a. Atomic mass decreases by two.
b. Atomic number increases by one.
c. Atomic mass increases by one.
d. Atomic number decreases by two.
[Ques. 5] The beta emission process results in the daughter nucleus differing in what manner from the parent?
a. Atomic mass changes by two.
b. Atomic mass changes by one.
c. Atomic number changes by two.
d. Atomic number changes by one.
[Ques. 6] Chromium-55 (54.9408 u) emits an electron leaving a daughter nucleus of manganese-55 (54.9380 u). How much energy is released in this reaction? (1 u = 931.5 MeV/c2)
a. 2.61 MeV
c. 5.59 MeV
b. 0.70 MeV
d. 1.40 MeV
[Ques. 7] When radium-224 emits an alpha particle, the remaining daughter nucleus is which of the following?
a. actinium-215
c. bismuth-215
b. lead-213
d. radon-220
[Ques. 8] Uranium-238 decays to Thorium-234 by emitting which of the following?
a. gamma ray
c. beta particle
b. positron
d. alpha particle
[Ques. 9] Tritium (3H) has a half-life of 12.3 years and releases 0.0186 MeV energy per decay. What is the rate at which energy is released for a 3.0-gram sample of tritium? (NA = 6.02 1023 mol1, 1 year = 3.16 107 s, 1 MeV = 1.6 1013 J, and mt = 3.01605 u)
a. 3.2 W
c. 9.6 W
b. 1.1 W
d. 0.33 W
[Ques. 10] Tritium (3H) has a half-life of 12.3 years and releases 0.0186 MeV energy per decay. What is the activity of a 9.0-gram sample of tritium? (NA = 6.02 1023 mol1, 1 year = 3.16 107 s, 1 MeV = 1.6 1013 J, and mt = 3.01605 u)
a. 1.3 1016 Bq
c. 3.6 1014 Bq
b. 1.1 1015 Bq
d. 3.2 1015 Bq
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