WorksheetsRadioactivity IGCSE 3
Total questions: 20
Worksheet time: 30mins
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
Compared with β-particles and γ-rays, α-particles
are the only type of radiation to carry a charge.
have the greatest ionising effect.
have the greatest penetrating effect.
have the smallest mass.
In a cathode-ray tube, a hot tungsten cathode releases particles by thermionic emission.
What are these particles?
α-particles
electrons
protons
tungsten atoms
The diagram shows a radioactive source, a thick aluminium sheet and a radiation detector.
The radiation detector shows a reading greater than the background reading.
Which type of radiation is being emitted by the source and detected by the detector?
α-radiation
β-radiation
γ-radiation
infra-red radiation
The count rate from a radioactive isotope is recorded every hour. The count rate is corrected forbackground radiation.
The table shows the readings.
What estimate of the half-life of the isotope can be obtained from the readings in the table?
between 1 and 2 hours
between 2 and 3 hours
between 3 and 4 hours
between 4 and 5 hours
BA radioactive source emits three types of radiation R, S and T.
The diagram shows an experiment set up to study the penetrating properties of R, S and T.
A
B
C
D
The half-life of a radioactive substance is 10 minutes. A sample of the radioactive substancecontains 2000 nuclei.
How many radioactive nuclei were in the sample half an hour earlier?
250
4000
6000
16 000
In a cathode-ray tube, particles are fired at a screen.
What are these particles?
α-particles
electrons
neutrons
protons
A raadtion detector is placed close to a source of β-particles.
Aluminium sheets of increasing thickness are placed between the source and the detector.
Eventually a sheet which is 2.0 cm thick is used. The reading on the detector decreases, but does not fall to zero.
Why does the reading not fall to zero?
Some of the β-particles go round the edges of the sheet.
The detector is too close to the source.
There is always some background radiation..
The sheet can never be thick enough to absorb all the β-particles
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 substance emits a particle from the nucleus of one of its atoms. The particleconsists of two protons and two neutrons.
What is the name of this process?
α-emission
β-emission
γ-emission
nuclear fission
Why are some radioactive sources stored in boxes made from lead?
Lead absorbs emissions from the radioactive sources.
Lead decreases the half-life of radioactive sources.
Lead increases the half-life of radioactive sources.
Lead repels emissions from the radioactive sources.
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 radioactive decay can be represented as shown.
The equation is incomplete.
In this decay, the nucleus changes by
absorbing a neutron.
absorbing a proton.
emitting an α-particle.
emitting a β-particle.
When measuring the emissions from a radioactive rock brought into the laboratory, a teacher mentions that background radiation must be taken into account.
What is this background radiation?
infra-red radiation from warm objects in the laboratory
infra-red radiation from the Sun
ionising radiation from the radioactive rock brought into the laboratory
ionising radiation in the laboratory when the radioactive rock is not present
Which row shows the relative ionising effects and penetrating abilities of α-particles and β-particles?
A
B
C
D
A powder contains 400 mg of a radioactive material that emits α-particles.
The half-life of the material is 5 days.
What mass of that material remains after 10 days?
0 mg
40 mg
100 mg
200 mg
A scientist needs to use a source of γ-rays as safely as possible.
Which action will not reduce the amount of radiation that reaches the scientist?
keeping the distance between the source and the scientist as large as possible
keeping the temperature of the source as low as possible
keeping the time for which the scientist uses the source as small as possible
placing a lead screen between the scientist and the source
The graph shows the activity of a radioactive source over a period of time.
What is the half-life of the source?
1/2 hour
1 hour
1 1/2 hours
3 hours
The arrangement shown is used to check whether the flour inside a cardboard packet is above a certain level. If it is above this level, the flour absorbs the radiation from the source so that it doesn’t reach the detector.
Which type of radiation is suitable to use?
α-particles only
β-particles only
either α-particles or β-particles
γ-rays only
