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Medical supplies, such as the bandage shown in the photograph, have to be sterilised before they are sold - Edexcel - GCSE Physics - Question 6 - 2017 - Paper 1
Question 6
Medical supplies, such as the bandage shown in the photograph, have to be sterilised before they are sold. There are two ways of sterilising medical supplies: - th... show full transcript
Worked Solution & Example Answer:Medical supplies, such as the bandage shown in the photograph, have to be sterilised before they are sold - Edexcel - GCSE Physics - Question 6 - 2017 - Paper 1
Step 1
Suggest one advantage of using radiation rather than high temperatures to sterilise medical supplies.
Answer
One advantage of using radiation to sterilise medical supplies is that it does not damage or alter the packaging or bandage material, whereas high temperatures can cause burns or melt the materials.
Step 2
Calculate how long it takes for the activity of a sample of cobalt-60 to fall to one quarter (25%) of its original value.
Answer
To determine how long it takes for the activity of cobalt-60 to fall to one quarter of its original value, we can use the concept of half-life. Since the half-life of cobalt-60 is 5 years, one half-life reduces the activity to 50% of the original. Another half-life reduces it to 25% of the original value. Thus, it takes a total of 2 half-lives to reach 25%:
Total time = 2 × 5 years = 10 years.