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A student watches a radioactivity demonstration - Edexcel - GCSE Physics - Question 2 - 2012 - Paper 1
Question 2
A student watches a radioactivity demonstration. The demonstration uses this arrangement. The teacher puts different materials in the holder. Then she measures the ... show full transcript
Worked Solution & Example Answer:A student watches a radioactivity demonstration - Edexcel - GCSE Physics - Question 2 - 2012 - Paper 1
Step 1
(i) Complete the sentence by putting a cross (✗) in the box next to your answer.
Answer
The radiation from the source is
☐ A alpha particles ☐ X B beta particles ☐ C gamma rays ☐ D X-rays
Answer: Cross (✗) next to B (beta particles) because the counts entering the detector are significantly lower with the other materials.
Step 2
(ii) The teacher returns the radioactive source to the box. Suggest why the box is lined with lead.
Answer
The box is lined with lead to prevent radiation from escaping. Lead is an effective shield against gamma and other forms of radiation, reducing the exposure to surrounding areas and ensuring safety.
Step 3
(iii) The counter still gives a reading. The teacher says this is caused by background radiation. State one source of background radiation.
Answer
One source of background radiation is cosmic rays from outer space. These rays are constantly bombarding the Earth and contribute to background radiation levels.
Step 4
(iv) The teacher takes precautions to protect her students from the radiation emitted by the radioactive sources. State two suitable precautions that protect the students.
Answer
- Maintain a safe distance between students and the radioactive source.
- Use protective barriers, such as lead-lined boxes, to block radiation exposure.
Step 5
(i) A sample of air contains 6 mg of radon. Radon has a half-life of 4 days. Calculate the mass of the radon remaining after 8 days. Show your working.
Answer
To find the remaining mass of radon after 8 days:
-
Determine the number of half-lives:
\frac{8 ext{ days}}{4 ext{ days/half-life}} = 2 ext{ half-lives}
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Calculate the remaining mass:
.
Step 6
(ii) Some places have rocks which release radon gas. Explain why people living in these places may have an increased risk of long-term health problems.
Answer
People living in areas with rocks that release radon gas may have an increased risk of long-term health problems because radon is a known carcinogen. Prolonged exposure to radon can lead to lung cancer, as inhaled radon decays into radioactive particles that can damage lung tissues.