9.6 Nature of Radioactive Decay Flashcards
The emission of radiation is said to be?
spontaneous and random
What is the meaning of random ?
Unpredictable
What is the meaning of spontaneous?
unaffacted by external factors(temp pressure etc.), happens with no warning
What does this mean?
We cannot tell which nucleus will decay next nor when it will decay
Why can we use statistical methods , and what would we use them for?
If we have a large number of nuclei involved.
We can work out how long it will take for the next one to decay.
What is the decay constant?
fraction of atoms that will decay in the next second/hour/day(any time frame)
Another name for rate of decay?
the activity
What is the equation for activity/rate of decay? What do the symbols represent and what are their units?
A/Rate of decay = -dN/dt = ΛN A/Rate of decay = Activity (Bq or s^-1) Λ = decay constant (s^-1) (or any time frame) N = number of nuclei (undecayed) t = time (change in time)(s)
Why is -dN/dt in this equation negative?
since the size of sample decreases with time
What is activity proportional to?
the size of sample (the undecayed nuclei)
The unit of Bq is equal to what SI unit?
s^-1
Why does the rate have a negative number?
As the number of nuclei decreases.
