4.2.4-Half-life Flashcards
1
Q
First meaning of Half-life
A
Is the average time taken for the number of radioactive nuclei to halve.
2
Q
The activity of a radioactive substance is measured
A
In Becquerel (Bq)
3
Q
Count rate
A
The number of radioactive counts reaching per second.
4
Q
Half-life
A
The time taken for the activity to fall to half of its initial value.
5
Q
The calculation
A
The level of radiation due to substance=
Level of radiation with substance + background radiation -
Level of background radiation
6
Q
How to work out the level of background radiation?
A
By using a Geiger counter
7
Q
Does a substance’s mass halve over a half-life?
A
No, the half-life is not the time taken for the mass of a radioactive sample to halve.
