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Total questions: 20
Worksheet time: 5hrs 0mins
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 B 6.4 hours C 8.0 hours D 16 hours
2,0 hours
6,4 hours
8,0 hours
16 hours
The graph shows how the decay rate of a radioactive source changes with time.
What will be the decay rate at 8 days?
0 decays/s
125 decays/s
250 decays/s
500 decays/s
The reading on a detector placed near a radioactive material is 536 counts per second.
The background count rate is 44 counts per second.
The half-life of the radioactive material is 34 hours.
What is the reading on the detector after 68 hours?
44 counts/s
123 counts/s
134 counts/s
167 counts/s
A powder contains 400mg 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
The counter of a radiation detector placed close to a radioactive source gives a count rate of 1600 counts / s.
The half-life of the source is 1 week.
Ignoring background radiation, calculate the count rate 1 weeks after the first measurement....
800 counts / s
200 counts / s
400 counts / s
100 counts / s
A reading is taken every 10 minutes of the number of emissions per second from a radioactive source. The table shows the readings.
What is the half-life of the source?
10 min
20 min
40 min
60 min
The half-life of a radioactive substance is 10 minutes. A sample of the radioactive substance contains 2000 nuclei. How many radioactive nuclei were in the sample half an hour earlier?
250
4000
6000
16000
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
The count rate from a radioactive isotope is recorded every hour. The count rate is corrected for background 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
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
A radioactive isotope is placed near a detector.
The readings on the detector are corrected for background radiation and recorded every hour.
The table shows the corrected readings.
What is the half-life of the isotope?
between 0 and 1 hour
between 1 hour and 2 hours
between 2 hours and 3 hours
between 3 hours and 4 hours
A radioactive substance has a half-life of 2 weeks. At the beginning of an investigation, a sample of the substance emits 3000 β-particles per minute.
How many β-particles will it emit per minute after 6 weeks?
0
375
500
1500
A sample of a radioactive isotope has an initial rate of emission of 128 counts per minute and a half-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
Which row describes the nature of α-particles and of γ-rays?
A
B
C
D
Which row gives the properties of the radiation from radioactive materials?
A
B
C
D
Which statement about α-radiation is correct?
It is a stream of fast-moving electrons.
It is a form of electromagnetic radiation.
It is more highly ionising than γ-radiation.
It is more penetrating than β-radiation.
α, β and γ-radiations are emitted by radioactive substances. Which statement is correct?
α-radiation consists of charged particles and is the most highly ionising radiation.
β-radiation consists of charged particles and is the most penetrating radiation.
β-radiation consists of uncharged particles and is the least highly ionising radiation.
γ-radiation consists of uncharged particles and is the least penetrating radiation.
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
In a cathode-ray tube, a hot tungsten cathode releases particles by thermionic emission.
What are these particles?
α-particles
electrons
protons
tungsten atoms
A 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.
Which types of radiation are R, S and T?
R: α-particles, S: β-particles, T: γ-rays
R: α-particles, S: γ-rays, T: β-particles
R: β-particles, S: α-particles, T: γ-rays
R: γ-rays, S: β-particles, T: α-particles
