Edexcel IGCSE Physics 7.6 radiation penetration practical
Practise radiation practicals by choosing absorbers, measuring count rate, subtracting background and judging conclusions from data.
- Syllabus
- First assessment 2019
- Course
- Physics 4PH1
Exam points
- Describe using a GM tube and counter to compare count rates with different absorbers.
- Control absorber thickness and subtract background count to make penetration results valid.
- Choose a bar chart for absorber type and evaluate the best absorber from count rate.
7.6 Radiation penetration practical question 1
A teacher investigates the penetrating ability of the gamma rays from a gamma source.
This is the teacher's method.
- place the gamma source at a distance of 25 cm from a radiation detector
- place a 1 cm thick absorbing material between the source and the detector
- measure the radiation count from the source for a time period of 3 s
- calculate the count rate in counts per second
- repeat the measurement two more times
The teacher repeats this method for different absorbing materials.
Question (a)
(a)
State the independent variable in the teacher's investigation.
[ 1 ]
Question (b)
(b)
Explain why every absorbing material used in the investigation has a thickness of 1 cm .
[ 2 ]
Question (c)
(c)
Suggest one improvement the teacher could make to this method.
[ 1 ]
Question (d)
(d)
The table shows the teacher's results for seven different absorbing materials.
[ 5 ]
Question (i)
(i)
On the grid, plot a bar chart of the mean count rate for each absorbing material.
[ 3 ]
Question (ii)
(ii)
A student concludes that plastic is the best absorber of gamma radiation because plastic gives the largest mean count rate.
Evaluate the student's conclusion.
[ 2 ]
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