A seed bank holds a sample that is 98 per cent viable when stored…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A seed bank holds a sample that is per cent viable when stored. A sample is grown out to make fresh seed when its viability falls to per cent. In the model the viability halves every years. (This model is not in the NEET syllabus.)
- After how many years must the sample be grown out? Give one decimal.
- If the half-life were years, how many years would it be?
- If the limit were per cent and the half-life years, how many years would it be?
Need a reminder? The key ideaShow
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Given. , limit , years.
Plan. .
Step 1. (a) . So years.
Step 2. (b) The time is proportional to , so years.
Step 3. (c) . So years.
Answer: years; years; years.
Check. A higher limit is reached sooner, and a shorter half-life is reached sooner.
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