Photo AI
A teacher uses a Geiger-Müller tube and a counter to measure background radiation - Edexcel - GCSE Physics - Question 5 - 2016 - Paper 1
Question 5
A teacher uses a Geiger-Müller tube and a counter to measure background radiation. The reading on the counter tube is 34 counts per minute. (ii) The teacher puts a... show full transcript
Worked Solution & Example Answer:A teacher uses a Geiger-Müller tube and a counter to measure background radiation - Edexcel - GCSE Physics - Question 5 - 2016 - Paper 1
Step 1
Calculate how much radiation detected by the Geiger-Müller tube comes from the source of beta radiation.
Answer
To find the radiation from the source of beta radiation, we need to subtract the background radiation from the total reading:
Total reading with beta source = 468 counts per minute Background radiation = 34 counts per minute
Radiation from the source of beta radiation:
counts per minute
Thus, the radiation detected from the source of beta radiation is 434 counts per minute.
Step 2
Estimate the reading on the counter tube.
Answer
When the thick sheet of aluminium is placed between the beta source and the Geiger-Müller tube, it will absorb some of the beta radiation. Since beta particles have limited penetration, we can estimate that the counter reading will decrease significantly.
A reasonable estimate after the aluminium sheet might be around:
10 to 20 counts per minute.
Step 3
Give a reason why the answer to (ii) is only an estimate.
Answer
The answer to (ii) is only an estimate because the absorption of beta radiation by the aluminium can vary depending on several factors such as the energy of the beta particles, thickness and composition of the aluminium, and the distance from the source to the detector. Additionally, not all beta particles will be stopped by the aluminium, leading to uncertainty in the exact reading.