Finding half-life from a graph half-life The half-life in this example is about 30 seconds. A more accurate value can be obtained be repeating this method for a other initial nuclei numbers and then taking an average.
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Do Now Copy and complete : page 265 The ________ of a radioactive substance is the average time taken for half of the _______of the substance to decay. It is also equal to the average time taken for the ________ of the substance to halve. The half-life of carbon 14 is about _______ years. If today a sample of carbon 14 has an activity of 3400 Bq then in 5600 years time this should have fallen to ______ Bq. 11200 years later the activity should have fallen to ____ Bq. The number of carbon 14 nuclei would have also decreased by ______ times. eigh t half- life 560 0 425 activi ty 1700 WORD & NUMBER SELECTION: nucle i eigh t half- life 560 0 425 activit y 1700 nucle i
Transcript
Do Now Copy and complete : page 265
The ________ of a radioactive substance is the average time taken for half of the _______of the substance to decay. It is also equal to the average time taken for the ________ of the substance to halve.
The half-life of carbon 14 is about _______ years. If today a sample of carbon 14 has an activity of 3400 Bq then in 5600 years time this should have fallen to ______ Bq. 11200 years later the activity should have fallen to ____ Bq.
The number of carbon 14 nuclei would have also decreased by ______ times.
eight half-life5600 425 activity1700
WORD & NUMBER SELECTION:
nuclei
eight
half-life
5600
425
activity
1700
nuclei
Today’s lesson• Find the half life from graphs version 2.
• Give and explain examples of practical applications of isotopes.
Title Uses of radioactive isotopes
Finding half-life from a graph
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time (seconds)
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half-life
The half-life in this example is about 30 seconds.
A more accurate value can be obtained be repeating this method for a other initial nuclei numbers and then taking an average.
Question 6
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time (seconds)
activ
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Estimate the half-life of the substance whose decay graph is shown opposite.
half-life
Revision SimulationsHalf-Life - S-Cool section on half-life and uses of radioactivity including an on-screen half-life calculation and an animation showing thickness control.
BBC AQA GCSE Bitesize Revision: Detecting radiation Natural sources of background radiation Artificial radiation Half life
Alpha Decay - PhET - Watch alpha particles escape from a Polonium nucleus, causing radioactive alpha decay. See how random decay times relate to the half life.
