Question

The radioactive isotope thorium 234 has a half-life of approximately 578 hours.

If a sample has an initial mass of 64 mg, a function that models the mass in mg after t hours is a(t) =

The initial mass will decay to 12 mg after ______ hours

Radioactive decay equation:

a(t) = a0⋅2 ^ (−t / h)

a0 = starting amount

a(t) = amount after t hours

h = half life in hours

Answer #1

The radioactive isotope 198Au has a half-life of 64.8 hours. A
sample containing this isotope has an initial activity at (t=0) of
1.50e-12 Bq. Calculate the number of nuclei that will decay in the
time interval between t1=10 hours and t2=20 hours
Answer is 4.60e16 but I'm not sure how. Thanks and please show
work

The radioactive isotope 234Pa has a half-life of 6.70
h. A sample containing this isotope has an initial activity
(t = 0) of 35.0µCi. Calculate the number of nuclei that
decay in the time interval between t1 = 7.0 h
and t2 = 14.0 h.
___________ Nuclei

The radioactive isotope 198Au has a half-life of 64.8 hr. A
sample containing this isotope has an initial activity (t = 0) of
1.5x 10^12 Bq. Calculate the number of nuclei that decay in the
time interval between t1 = 10 hr and t2 = 12 hr.
Please show and explain work, and do not use calculus to solve
it.

The
radioactive isotope Gold-198 has a half-life of 64.80 hrs. A sample
containing this isotope has an initial activity of 40.0 μCi.
Calculate the number of nuclei that will decay in the time interval
from 10 hrs to 12 hrs.[10 marks]

A patient is given 0.045 mg of technetium-99 m , a radioactive
isotope with a half-life of about 6.0 hours. How long does it take
for the radioactive isotope to decay to 8.0×10−4 mg ?
(Assume no excretion of the nuclide from the body.)

Research shows that the radioactive isotope Plutonium-238 has a
half-life of 87.7 years
Use the following to construct a function that will model the
amount of Plutonium-238 remaining after t years, from an initial
amount of 15 kg.
Q(t)=Pert
Where Q(t) describes the amount of Plutonium-238 remaining after
t years from an initial quantity of P kg.
Q(t)=
How long (in years) will it take for the amount of
Plutonium-238 remaining to reach 3 kg?

Given the fact that the lifetime of 14C, the
radioactive isotope of carbon, is approximately 8267 years,
calculate how much time would pass before only 81.1% of the initial
amount of the 14C remains. (Note: the lifetime = half
life/ln (2) = half life/0.6931. The half life of 14C is
5730 years.)
Decay Time (in years):

A freshly prepared sample of a certain radioactive isotope has
an activity of 10.4 mCi. After 4.20 h, its activity is 8.00
mCi.
(a) Find the decay constant and half-life. decay constant s-1
half-life h
(b) How many atoms of the isotope were contained in the freshly
prepared sample?
(c) What is the sample's activity 33.7 h after it is prepared?
mCi

A radioactive isotope has a half-life of 72.0 min. A sample is
prepared that has an initial activity of 1.40×1011
Bq.
Q1: How many radioactive nuclei are initially present in the
sample?
Q2: How many are present after 72.0 min?
Q3: What is the activity after 72.0 min?
Q4: How many are present after 144 min?
Q5: What is the activity after 144 min?

An isotope of gallium, 67Ga, has an atomic number of 31 and a
half-life of 78 hours. Consider a small mass of 3.4 grams for 67Ga
which is initially pure.
1. Initially, what is the decay rate of the gallium? Ro =
2. What is the half-life of the gallium after 24 hours? T1/21
=
3. Initially, what is the initial decay constant of the Ga atoms
after 24 hours?
4. λ1 = What is the decay rate of the...

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