Q1.
Before using a radioactive source, a teacher asked her students to suggest safety
procedures that would reduce her exposure to the radiation. The students made the
following
(a)
Which suggestion, A, B or C, would not reduce the exposure of the teacher to
radiation?
........................................................................
(1)
(b)
The diagram shows how the teacher measured the distance that the radiation
traveled from the source. The count-rate at different distances from the source was
measured and recorded in the table.
Distance from source to Count-rate in counts
detector in cm
per minute
20
85
40
81
60
58
80
53
100
23
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What type of radiation was the source emitting, alpha, beta or gamma?
.....................................................................................................................................
Explain the reasons for your choice.
........................................................................................................ .............................
............................................................................................................................. ........
.....................................................................................................................................
............................................................................................................................. ........
(3)
(c)
The graphs show how two groups of scientists, A and B, link exposure to radiation
and the risk of getting cancer.
(i)
Complete the following sentence using a word or phrase from the box.
decreases
has no effect on
increases
Both groups of scientists agree that a high level of exposure to radiation
............................................................ the risk of getting cancer.
(1)
(ii)
Use the graphs to describe carefully how the two groups of scientists disagree
when the level of exposure to radiation is very low.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(Total 7 marks)
Page 2
Q2.
Four different processes are described in List A. The names of these processes are
given in List B.
Draw a line to link each description in List A to its correct name in List B.
Draw only four lines.
(Total 4 marks)
Page 3
Q3.
Four different processes are described in List A. The names of these processes are
given in List B.
Draw a line to link each description in List A to its correct name in List B.
Draw only four lines.
List A
List B
ionisation
the nucleus of an
atom splitting into
several pieces
gamma emission
the nuclei of two
atoms joining
together
nuclear fission
an atom losing an
electron
nuclear fusion
an electric charge
moving through a
metal
electric current
(Total 4 marks)
Page 4
Q4.
The diagram shows an atom.
How many protons are there in the nucleus of the atom? .................................................
What is the mass number of the atom? ..............................................................................
(Total 2 marks)
Q5.
The diagram shows a helium atom.
(a)
(i)
electron
Use the words in the box to label the diagram.
neutron
proton
(2)
(ii)
An alpha particle is the same as the nucleus of a helium atom.
How is an alpha particle different from a helium atom?
...........................................................................................................................
...........................................................................................................................
(1)
Page 5
(b)
The graph shows how the count rate from a sample of radioactive sodium-24
changes with time.
(i)
How many hours does it take for the count rate to fall from 100 counts per
second to 50 counts per second?
Time = .............................. hours
(1)
(ii)
What is the half-life of sodium-24?
Half-life = .............................. hours
(1)
(c)
A smoke detector contains a small amount of americium-241.
Americium-241 is a radioactive substance which emits alpha particles. It has a
half-life of 432 years.
(i)
Which one of the following statements gives a reason why the americium-241
inside the smoke detector will not need replacing?
Put a tick ( ) in the box next to your answer.
Page 6
The alpha particles have a low energy.
People replace smoke detectors every few years.
Americium-241 has a long half-life.
(1)
(ii)
The diagram shows the label on the back of the smoke detector.
Why do people need to know that the smoke detector contains a radioactive
material?
...........................................................................................................................
............................................................................................. ..............................
(1)
(Total 7 marks)
Page 7
M1.
(a)
C
1
(b)
beta
accept gamma
if answer alpha can still gain marks for saying why not beta
or gamma
1
any two from:
must have at least one quantitative statement to get 2 marks
•
range in air for beta is (at least) 50cm
•
count-rate does not drop (much) in first 40cm
•
count-rate does not fall much until distance is 60cm
•
alphas cannot travel more than 5cm in air / alphas
could not travel 100cm in air
accept alphas cannot travel that far
•
alphas would not be detected
•
gammas not absorbed by 100cm of air
accept gammas not stopped by air
accept gammas travel further than alphas and betas
strength of source is neutral
references to penetrating power is neutral
2
(c)
(i)
increases
1
(ii)
Group A think that (even a very small level of exposure) gives some risk
accept there is always a risk, no matter how small the level
of exposure
1
Group B think that there is no risk (from a very low level of exposure)
accept below a certain level of exposure there is no risk
no marks for a simple graph description
1
[7]
Page 8
M2.
four lines correct
allow 1 mark for each correct line
if more than 1 line is drawn from a box in List A, mark each
line incorrect
[4]
M3.
[4]
Page 9
M4.
•
4
•
9
each for 1 mark
[2]
M5.
(a)
(i)
all 3 labels correct
allow 1 mark for 1 correct label
2
(ii)
has no electrons
it = alpha
allow alpha has a positive(charge)
allow a helium (atom) has no (charge)
do not accept general properties of alpha
do not accept general answers in terms of size / density /
mass etc
1
(b)
(i)
15 (hours)
accept any answer between 14.8 and 15.2 inclusive
1
Page 10
(ii)
15 (hours) or their (b) (i)
1
(c)
(i)
americium-241 has a long half life
1
(ii)
any one from:
•
alpha (particles) are harmful to …
accept radiation / radioactive material is harmful to …
accept specific example of harm
eg can cause cancer
accept radiation is poisonous if ingested / inhaled
do not accept it is poisonous / in case of leakage
•
so they dispose of it safely / appropriately
•
so they don’t break it open / open it
accept do not touch the radioactive source
•
so they can make a choice about having a radioactive source (in the
house)
it = radioactive material
1
[7]
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