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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. (i) 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 start by subtracting the background radiation from the total counts detected:
Total reading with beta source = 468 counts/min Background reading = 34 counts/min
The radiation from the beta source is:
Thus, the radiation detected from the beta source 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 source and the Geiger-Müller tube, it will absorb some of the beta radiation. As beta particles can be absorbed significantly by a few millimeters of aluminium, the reading on the counter tube will be lower than when the beta source was directly exposed.
An estimated reading could range from 0 to a few counts per minute, depending on the thickness of the aluminium.
A reasonable estimate could be about 50 counts per minute, but this varies based on the actual experimental conditions.
Step 3
Give a reason why the answer to (ii) is only an estimate.
Answer
The answer is only an estimate because the actual reduction in counts depends on various factors, such as the exact thickness of the aluminium, the energy of the beta particles, and possible scattering effects. There can also be variations in background radiation, which might affect the reading.