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Exponential decay: Half-life
- Lesson: 110:11
Exponential decay: Half-life
In the field of nuclear physics, half-life refers to the amount of time required for radioactive substances to decay into half. In this lesson, we will work on word questions about exponential decay of radioactive substances.
Related Concepts: Derivative of inverse trigonometric functions, Derivative of logarithmic functions
Lessons
exponential growth/decay: Af=Ai(f)periodtime
Af: final amount
Ai: initial amount
f : growth/decay factor
half-time→f=21
triple→f=3
ten-fold→f=10
increase by 10%→f=(1+10010)=1.1
decrease by 8%→f=(1−1008)=0.92
time : total time given
period : every length of time
Af: final amount
Ai: initial amount
f : growth/decay factor
half-time→f=21
triple→f=3
ten-fold→f=10
increase by 10%→f=(1+10010)=1.1
decrease by 8%→f=(1−1008)=0.92
time : total time given
period : every length of time
- 1.half-life decay
Strontium-90 is a radioactive substance with a half-life of 28 days.
How many days will it take for a 200 gram sample of strontium-90 to be
reduced to 8 grams?