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WorksheetsA2 nuclear physics
Total questions: 25
Worksheet time: 16mins
Name
Class
Date
1.
Protactinium has a half-life of 70 s. A sample of protactinium is prepared and monitored over a period of time. Which of the following statements is correct?
a)
The activity of the protactinium will be zero after 140 s.
b)
The activity of the protactinium will be 25% of its initial value after 140 s.
c)
The activity of the protactinium will be 12.5% of its initial value after 280 s.
d)
The activity of the protactinium will never become zero.
2.
In a famous thought experiment, Schrödinger imagined that a cat is locked in a box, along with a radioactive atom that is connected to a tube containing a deadly poison. If the atom decays, it causes the tube to smash and the cat to die. The random nature of radioactive decay means that the radioactive atom will
a)
decay after one half life
b)
probably decay after one half-life.
c)
have a fixed probability of decaying in a given time interval
d)
have a number of possible decay paths.
3.
The fuel used in a nuclear fission reactor is uranium. Which of the following is required for fission to proceed?
a)
Neutrons must be removed from the reactor core.
b)
The reactor core must be very hot
c)
The uranium nuclei must absorb neutrons
d)
The uranium nuclei must absorb protons
4.
A radioactive source is placed a few cm away from a detector. There is no change in the count rate when a thin aluminium foil is placed between the source and the detector, but the count rate is reduced to the background rate when a 0.5 cm aluminium plate is introduced. These observations show that the source must be emitting
a)
alpha and beta radiation
b)
beta and gamma radiation
c)
beta radiation only
d)
gamma radiation only
5.
The force that causes protons and neutrons in the nucleus to attract to one another is the
a)
strong nuclear force
b)
electric repulsion
c)
gravity
d)
weak force
6.
Fission and fusion are both nuclear processes. Which of the following statements is correct for both processes?
a)
Neutrons are released
b)
No harmful radiation is produced
c)
The binding energy per nucleon increases.
d)
The total mass increases
7.
When measuring the count rate from a radioactive source it is usual to also measure the background count rate. The background count rate must be
a)
as large as possible for an accurate experiment
b)
measured when the source is in place
c)
recorded for the same time as the count rate
d)
subtracted from the count rate measured from the source
8.
The ionising properties of radiations determine their penetrating power. Which of the following statements is correct?
a)
Alpha particles are not very ionising so they are stopped by thin paper
b)
Alpha particles are very ionising so they can only travel a few cm in air
c)
gamma radiation is very penetrating because it's very ionising
d)
gamma radiation is not very penetrating because it is very ionising
9.
Radioactive decay is sometimes described as being spontaneous. In this context spontaneous means
a)
nothing can influence the decay
b)
the decay is random
c)
the decay can be predicted
d)
the decay is exponential
10.
The total number of free neutrons immediately after a fission reaction
a)
goes down
b)
goes up
c)
may increase or decrease
d)
must stay constant
11.
Which of the following statements about nuclear fission is correct?
a)
A uranium-235 nucleus can only undergo fission after absorbing a proton.
b)
Kinetic energy is conserved during fission
c)
Linear momentum is not conserved during fission.
d)
The fission fragments have a total mass less than that of the nucleus just
before fission.
12.
Which particle type travels the fastest?
a)
alpha particles
b)
beta particles
c)
neutrons
13.
A(n) ______ nucleus will have a longer half-life.
a)
stable
b)
unstable
c)
heavy
d)
light
14.
Which produces more energy--nuclear fission or nuclear fusion?
a)
Fusion
b)
Fission
c)
They produce the same amount
d)
It depends on the elements used
15.
If we start off with element 24X50 after an alpha decay we get another element Y that looks like
a)
22Y50
b)
22Y46
c)
20Y48
d)
26Y54
16.
If we start off with element 24X50 after an gamma decay we get another element that looks like
a)
24X50
b)
23X50
c)
24X50
d)
25X50
17.
The count rate of an isotope falls from 1000 to 100 in a time of 6 hours. Which of the follwing is closest to the half life of the isotope?
a)
1 hour
b)
2 hours
c)
4 hours
d)
6 hours
18.
What is meant by the statement that 15P32 has a half life of 14 days
a)
It takes 7 days to go down to 50% radioactivity each time
b)
It takes 14 days to go down to 50% radioactivity each time
c)
After 14 days it starts to become less radioactive
d)
It takes 14 days to go up by 50% radioactivity each time
19.
Critical Mass
a)
is a splitting of a heavy atom into lighter atoms
b)
is the amount of material required so that each fission produces 1 more fission reaction
c)
2 light atoms together form a heavier atom
d)
4 hydrogen nuclei fuse to form a helium nucleus
20.
Half life
a)
process of changing one element to another
b)
amount of time it takes for half of the nucleotides to decay
c)
half of your life is over
d)
1/2 of the substance
21.
If you start with 100 grams of iodine-131 and the half life is 2 days, how many grams is left after 6 days?
a)
25
b)
12.5
c)
50
d)
200
22.
Protons and neutrons are made of even smaller particles called
a)
electrons
b)
atoms
c)
quarks
d)
metal
23.
A proton is made up of two up quarks and one down quark with charges of +2/3, +2/3, and –1/3.
a)
True
b)
False
c)
More information is needed
24.
A baryon is
a)
made of a quark and an anti-quark
b)
made of 3 quarks
c)
a fundamental particle
25.
A neutrino is emitted during
a)
alpha decay
b)
beta decay
c)
positron decay
d)
gamma decay
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