1] Define the 3 different radiations
emitted
by radioactive nuclei. Include a
Answer: Alpha, Beta, Gamma ; see text for descriptions!
5]
The atomic mass of the isotope 105B is 10.012938 u (this
includes the
electrons, don’t forget them). What is the binding energy per
nucleon
for this isotope?
Answer: 6.475
MeV/nucleon
1]
A
possible step in the fusion reactions for the Sun has a
hydrogen nucleus (1.00728 u)
fusing with a 7Be nucleus ( 7.01470 u ) to
form a
Boron nucleus ( 8B, 8.02186 u ) with the emission of a
gamma
ray. Write out the nuclear reaction
equation for this process and determine the maximum energy (in MeV)
of that gamma ray?
Answer:
11H + 74Be ------- 85B + 00gamma
0.11 MeV
2] A hospital receives a
supply of
radioactive iodine-131 that contains 3.00 x 1018 nuclei.
The
supply is kept isolated and when
measured exactly 1 year later, the supply contains
only
5.57 x 104 nuclei.
(B)
Determine the activity (in Bq) of the
iodine-131 material that remains after the 1 year isolation period.
Answer: 5.58 x 10(-2) Bq
Multiple Choice
1. The advantage of a fusion reactor when
compared to a fission reactor is which of the following?
A. the fuel is cheaper
B. there would be much less radioactive waste material
C. it takes less energy to cause fusion than it does
fission.
D. both choice A and B are valid
2. Which particle below is the least stable (ie. can
decay ) over time?
A. proton
B. neutron
C. electron
D. photon
3. Uranium-238 decays into the element Thorium-234. Which
of the following must be emitted in this one decay process?
A. gamma ray
B. beta particle
C. alpha particle
D. positron
E. neutron
4. Approximately how many half-life periods would have to elapse
if the activity of a radioactive isotope sample is to be reduced to
1/60 of its original value?
A. 2
B. 4
C. 6
D. 12
E. 16
Answers:
1. d
2. b
3. c
4. c