Figure 1 shows a sealed radioactive source used in schools and colleges - AQA - A-Level Physics - Question 1 - 2019 - Paper 3
Question 1
Figure 1 shows a sealed radioactive source used in schools and colleges.
State two safety procedures to reduce risk when using this type of source.
A sealed source... show full transcript
Worked Solution & Example Answer:Figure 1 shows a sealed radioactive source used in schools and colleges - AQA - A-Level Physics - Question 1 - 2019 - Paper 3
Step 1
State two safety procedures to reduce risk when using this type of source.
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Answer
Maximizing Distance: Always use tools to handle the source, keeping it at least 2 meters away from yourself and others to minimize exposure.
Limiting Exposure Time: Minimize the amount of time spent near the source during experiments to reduce radiation dose.
Step 2
Determine the number of routes by which B can change into K.
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Answer
By analyzing Figure 2, observe the pathways leading from B to K. Count the branching routes involving α and β decay paths.
The number of routes from B to K is 3.
Step 3
Identify which of the nuclei A to M are common to all the possible ways that ²²⁶Ra decays into ²⁰⁶Pb.
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Nuclei that are common to all decay routes include D and E, as they appear in every path from A to M leading to ²⁰⁶Pb.
Step 4
State and explain procedures to eliminate systematic error in the measurements used to find A₀.
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Calibration of Equipment: Ensure the radiation detector is calibrated before the measurement to provide accurate readings.
Background Measurement: Measure the background radiation with the source removed; average the readings to minimize statistical errors in A₀.
Step 5
Deduce the minimum thickness of the aluminium absorber that should be used in the experiment.
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Answer
Using Figure 4, observe that the maximum range for Eᵦ at 5.5 MeV is approximately 12 mm. Therefore, the minimum thickness of aluminium required is at least 12 mm.
Step 6
Deduce d using Figure 6.
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Analyzing the graph in Figure 6, note the linear relationship. If the gradient equals k, it can be written as:
d = k imes rac{1}{ ext{sqrt}(A)}
Using the scale, if k = 100 mm for any given count rate, it implies appropriate units are in mm.
Step 7
Determine e using Figure 6.
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Answer
Utilizing the relationship from earlier calculations and the confirmed plot in Figure 6, e can be solved as:
e = d - rac{A ext{given}}{k}
Substituting the known values would provide a final answer in mm.
