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Worksheetsradioactivity
Total questions: 60
Worksheet time: 3600secs
A lithium nucleus contains 3 protons and 4 neutrons.
What is its nuclide notation?
A nuclide is represented by the symbol PQ X.
How many neutrons are in one nucleus of the nuclide?
P
Q
P + Q
P – Q
The graph shows how the count rate on a detector due to a radioactive source changes with time.
What is the count rate at 5.0 hours?
960 counts per minute
600 counts per minute
150 counts per minute
0 counts per minute
A radioactive nucleus emits a β-particle.
What happens to the proton number (atomic number) of the nucleus?
It stays the same.
It increases by 1.
It decreases by 2.
It decreases by 4.
A certain element has several isotopes.
Which statement about these isotopes is correct?
They must have different numbers of electrons orbiting their nuclei.
They must have the same number of neutrons in their nuclei.
They must have the same number of nucleons in their nuclei.
They must have the same number of protons in their nuclei.
The graph shows how the decay rate of a radioactive source changes with time.
What will be the activity at 8 days?
0 decays / s
125 decays / s
250 decays / s
500 decays / s
Radioactive materials should be handled carefully.
Which safety precaution does not reduce the risk to people using a radioactive material?
keeping the material a long distance from people
keeping the material at a low temperature
using lead screening between the material and people
using the material for only a short time
A sample of a radioactive isotope has an initial rate of emission of 128 counts per minute and ahalf-life of 4 days.
How long will it take for the rate of emission to fall to 32 counts per minute?
2 days
4 days
8 days
12 days
A powder contains 400 mg of a radioactive isotope that emits α-particles.
The half-life of the isotope is 5 days.
What mass of this isotope remains after 10 days?
0 mg
40 mg
100 mg
200 mg
In a laboratory, a detector of ionising radiation records an average background count rate of
8 counts per second.
A radioactive source is now placed close to the detector. The count rate on the detector rises to
200 counts per second.
What is the count rate due to radiation from the radioactive source?
25 counts /s
192 counts / s
200 counts / s
208 counts / s
A radioactive source produces a count rate on a detector of 1600 counts / s.
After 32 hours the count rate has fallen to 100 counts / s.
Both count rates have been corrected for background radiation.
What is the half-life of the source?
2.0 hours
6.4 hours
8.0 hours
16 hours
A radioactive substance has a half-life of 2 weeks. At the beginning of an investigation, a sampleof the substance emits 3000 β-particles per minute.
How many β-particles will it emit per minute after 6 weeks?
0
375
500
1500
The table shows the results of an experiment to find the half-life of a radioactive substance.
What is the half-life of the substance?
60 seconds
120 seconds
180 seconds
240 seconds
What fraction of an isotope has decayed after 4 half lives?
3/4
7/8
15/16
1/2
When nuclei decay, massive amounts of __________ is released.
energy
electrons
protons
neutrons
Nuclear power plants have many disadvantages. One of those disadvantages is...
reduced CO2 emissions
stable power
nuclear waste
reduced pollution to our atmosphere
How can radioactivity be useful? =
It can be used to microwave food
It can be used in cancer treatments and pacemakers
It can be used to create helpful gamma rays
It can be used to create radioactive waste
Mass defect is
mass difference between mass of nucleon and mass of nucleus
mass difference of nucleus before reaction and mass of nucleus after reaction
energy required to separate completely all the nucleons in nucleus
energy released in nuclear reaction
What is the Half Life of this isotope?
3 days
5 days
8 days
10 days
A certain radioactive sample has a half life of 2 years. After 6 years, how much of the sample is left?
1/2
1/3
1/16
1/8
The half-life of Zn-71 is 2.4 minutes. If one had 100.0 g at the beginning, how many grams would be left after 2.4 minutes has elapsed?
100.0g
50.0g
12.5g
8.5g
If 10 mg of iodine 131 is given to a patient, how much is left after 8 days? The half-life of iodine-131 is 8 days.
5.0mg
1.25g
10g
10mg
The half-life of Zn-71 is 2.4 minutes. If one had 100.0 g at the beginning, how many grams would be left after 4.8 minutes has elapsed?
100.0g
25.0g
12.5g
8.5g
If 10 mg of iodine 131 is given to a patient, how much is left after 16 days? The half-life of iodine-131 is 8 days.
5.0mg
2.5mg
10g
10mg
Identify the missing substance in each of the following nuclear reaction.
_____→13756 Ba + 0−1 e
13755Ba
13757La
13856Ba
13755Cs
Cosmic radiation comes from ....
Nuclear bombs
Nuclear Power stations
Space
Earth's core
Isotopes in objects
Figure shows a radioactivity experiment carried out by a student. The results of the experiment are given in the table. The radiation emitted by the source are
α-particles
β-particles
γ-rays
α-particles and γ-rays
The decay of radium-226 is given by the following formula. The energy released by the decay is
2.64×10−21J
4.77×10−19J
5.99×10−14J
7.92×10−13J
6.65×10−11J
___________ starts the fission of a uranium atom.
Energy
Protons
One Neutron
All of the above
What is the role of the control rods in a nuclear reactor?
Absorb Gamma Radiation
Release Alpha Particles
Fuse Unstable Nuclei
Absorb Neutrons
What is the role of the moderator in an nuclear reactor?
Increase kinetic energy of neutrons
Watch out for nasty nasty comments posted by the neutrons
Slow neutrons to thermal neutrons so they can be absorbed by uranium
absorb neutrons so they do not go to create a chain reaction
Ash was found to have 12.5% as much carbon-14 as found in similar ash. How long ago was the ash formed? The half-life of C-14 is 5730 years
14080 years
11460 years
17190 years
2865 years
Nitrogen-13 has a half-life of 15 minutes. How much of a 320 gram sample of N-13 would remain after decaying 45 minutes?
20g
40g
60g
80g
Radon has a half-life of 4 days. How long does it take for 16 grams of radon to be reduced to 2 grams of radon?
6 days
9 days
10 days
12 days
Those patients who develop tyroid cancer are treated with a certain radioactive isotope before attending surgery. The isotope is ...
As-74
Tc-99
I-131
Na-24
The radioactive surgery used in archaeology to date organic remains is...
C-12
U-238
C-14
U-235
A beam of γ-rays passes between two charged metal plates as shown in the diagram. How do the γ-rays pass between the two charged plates?
The rays are deflected in a direction perpendicular to the page
The rays are deflected towards the negative plate.
The rays are deflected towards the positive plate.
The rays will continue in the same direction.
The diagram shows a box used for storing radioactive sources. Which material is best for lining the box to prevent the escape of most radioactive emissions?
aluminium
copper
lead
steel
Which of the following half-lives would be most suitable for a medical tracer used in a patient?
3 minutes
3 hours
3 days
3 years
Radioactive decay is the _________ and _________ disintegration (decay) of an _________ nucleus to become a more stable nucleus by the emission of energetic particles/photons/radioactive radiations.
controlled, spontaneous, unreactive
spontaneous, random, unreactive
controlled, random, unstable
spontaneous, random, unstable
The diagram above shows the visible tracks in a cloud chamber for
alpha particles
beta particles
gamma rays
During a nuclear fission, the amount of energy released is 1.650 x 10-3 J. What is the mass defect in the nuclear reaction? (Speed of light = 3.00 x 108 ms-1)
5.5 x 10-12 kg
9.075 x 10-15 kg
1.833 x 10-20 kg
3.025 x 10-23 kg
Which radioactive detector device is not suitable to detect gamma ray?
Spark counter
Geiger-Muller tube
Photographic film
Cloud chamber
Nuclide 21483 Bi undergoes a series of decays to become 20682 Pb. Determine the number of alpha particles and beta particles emitted in this decay series.
2 alpha particles and 3 beta particles
3 alpha particles and 4 beta particles
3 alpha particles and 2 beta particles
2 alpha particles and 4 beta particles
A sample of protactinium-234 of mass 100 g has a half-life of 6.7 hours. What is the mass of decayed protactinium-234 after 20.1 hours?
12.5 g
25.0 g
50.0 g
87.5 g
A bone found at an archaeological site has a carbon-14 activity which is 6.25% the activity of a live animal. What is the age of the bone? (Half-life of carbon-14 = 5730 years)
5730 years
11460 years
17190 years
22900 years
Which of the following radioisotopes is used for detection of leaks in underground pipes?
Uranium-238
Sodium-24
Phosphorus-32
Bismuth-213
Which part of the nuclear reactor is responsible for reducing the rate of fission?
Graphite moderator
Boron Control Rods
Water
Uranium rods
Why can only alpha radiation be used in smoke detectors
It is required to ionise the air in a detector and be absorbed by the smoke
It is the only type of radiation which would not be absorbed by the smoke
It is the least dangerous type of rdiation
Other types of radiation would be able to leave the detector and pose a threat to the people in the house
