42) What is the radioactive particle released in the following nuclear equation?
38 Sr 39 Y + ?
A) alpha particle
B) beta particle
C) gamma ray
43) When aluminum-27 is bombarded with a neutron, a gamma ray is emitted. What radioactive isotope is
44) The unit used to measure the amount of radiation absorbed by a gram of material is called the
45) The half-life of a radioisotope is
A) one-half of the time it takes for the radioisotope to completely decay to a nonradioactive isotope.
B) the time it takes for the radioisotope to become an isotope with one-half of the atomic weight of the
C) the time it takes for the radioisotope to become an isotope with one-half the atomic number of the original
D) the time it takes for the radioisotope to lose one-half of its neutrons.
E) the time it takes for one-half of the sample to decay.
46) Sodium-24 has a half-life of 15 hours. How many hours is three half-lives?
A) 60 hours
B) 45 hours
C) 30 hours
D) 15 hours
E) 7.5 hours
47) A wooden object from a prehistoric site has a carbon-14 activity of 10 counts per minute (cpm) compared to 40
cpm for new wood. If carbon-14 has a half-life of 5730 years, what is the age of the wood?
A) 1430 yr
B) 5730 yr
C) 11,500 yr
D) 17,200 yr
E) 22,900 yr
48) In the sun, nuclei of hydrogen combine to form a larger nucleus and release a great amount of energy. The
process is known as
D) chain reaction.
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