Strontium-90 decays to Y-90 by beta decay with a half-life of 28
yrs. Y-90 decays by...
Strontium-90 decays to Y-90 by beta decay with a half-life of 28
yrs. Y-90 decays by beta decay-to Zircomium-90 with a half-life of
64 hrs. What is the composition of the original Strontium -90
sample after (a) 1 hr, (b) 10 yrs?
Rubidium-87 decays by β production to strontium-87 with a half
life of 4.7 × 1010 years. What is the age of a rock
sample that contains 105.9 µg 87Rb and 7.9 µg
87Sr ?
____ years old
Assume that no 87Sr was present when the rock was
formed.
The atomic masses are given in the table below:
Nuclide
Atomic Mass
87Rb
86.90919
87Sr
86.90888
Rubidium-87 decays by β production to strontium-87 with a half
life of 4.7 × 1010 years. What is the age of a rock
sample that contains 104.6 µg 87Rb and 7.1 µg
87Sr ?
Assume that no 87Sr was present when the rock was
formed.
The atomic masses are given below:
Nuclide
Atomic Mass
87Rb
86.90919
87Sr
86.90888
The half-life for the alpha decay of
232U to form
228Th is
68.9 y. Suppose the energy of the
alpha particle is 5.28 MeV and that
1.09 g of
232U, freed of any
other radioactive materials, were placed in a calorimeter
containing 49.1 g of water, initially at
22.9°C. Calculate the temperature the water would
reach after 1.15 hour. Neglect the heat capacity
of the calorimeter and heat loss to the surroundings. Take the
specific heat of water to be...
3816S decays by beta emission to
3817Cl. This reaction has a half‐life of
2.87 hours. The 3817Cl subsequently decays
by beta emission to 3818Ar. This reaction
has a half‐life of 37.3 min.
a) How much will remain of an initially pure sample of 3.5 mg
3816S after 9.35 hours?
b) How many mg of 3817Cl will be present
after 9.35 hours?
c) How many mg of 3818Ar will be present
after 9.35 hours?
Radioactive Decay
Objective: to study the radioactive decay of materials.
Understand the concept of half life and randomness of
the radioactive decay
Run the case of H3 decay to He3:
Go to “Multiple Atoms” tab
Start with 80 atoms by clicking on the bucket.
Start running and record the time when the number of H3 is
changing to 40, 20, 10, and 5.This is accumulative time
Repeat the above step 5 times and average them
(below is an example of table...
a) Radon undergoes alpha decay with a half-life of 3.8 days.
What is its decay constant in s-1?
b) Sr -90 (A=90, Z = 38) decays via β- decay.
Calculate the energy of the antineutrino (in keV) if the beta
particle has a kinetic energy of 397 keV. Note - you can look the
atomic masses up online.
c) What is the average binding energy per nucleon for Argon-40
(A=40, Z = 18) in MeV/nucleon? Note - keep 4 significant...
Strontium 38Sr90 has a half-life of 29.1 yr. It is chemically
similar to calcium, enters the body through the food chain, and
collects in the bones. Consequently, 38Sr90 is a particularly
serious health hazard. How long (in years) will it take for
99.9488% of the 38Sr90 released in a nuclear reactor accident to
disappear?
The Plutonium isotope 239Pu has a half-life of 24,000 years and
decays by the emission of a 5.2 MeV alpha particle. Plutonium is
not especially dangerous if handled because the activity is low,
and the alpha radiation doesn’t penetrate the skin. However, there
can be serious health concerns if the tiniest particles are inhaled
and lodge deep in the lungs. This could happen following any kind
of fire or explosion that disperses Plutonium as dust.
a) (3 pts.) Soot particles...
The half-life of carbon-14 is 5730 years. Assume that the decay
rate is proportional to the amount. Find the age of a sample in
which 10% of C-14 originally present have decayed.
Select the correct answer.
a.
950 years
b.
1050 years
c.
1150 years
d.
850 years
e.
none