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Half Life Graph Calculation with Count Correction GCSE Physics
>> YOUR LINK HERE: ___ http://youtube.com/watch?v=jemER9PxNV4
A graph of Count Rate vs Time can show the decay of a radioactive isotope. *** Please note mistake at 4:18 - should be days, not hours! :) • The half-life of the radioisotope can be calculated from this graph, but the background radiation will first need to be subtracted. • This video takes you through the calculation of half life using a background count correction. • The original graph show the count rate of the sample, but ALSO includes the background radiation count. • We can obtain the 'pure' count rate by subtracting the background count. So how do we find the background count? • The background count is 20cpm because that is what's left after the sample has decayed (i.e. from 8 hours onwards). • So the first point on the new graph is 100 - 20 = 80cpm at t=0 • The second point on the new graph is 60-20 = 40cpm at t=1 • and so on... • Check out more GCSE physics tutorials at http://gcsephysicsninja.com
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