1. 30-8 Half-Life and Rate of Decay
N = -l N D t
l Is called the decay constant.
Half-life it the time for half of the radio-active nucleus to decay.
Radioactive decay law….equation 30-4
DN= No e -lt .
DN is number of decays that occur in time t.
No is the number of radioactive nuclei present
The precise relationship between half-life and decay constant is T1/2 . = .693/ l

2. 10-9 continued
See Example 30-7 and 30-8

3. 30-10 Decay Series
See chart on page 933

4. 30-11 Radioactive dating
Using this very accurate ‘clock’ you can determine how much isotope has decayed and determine the age of a radioactive nucleus/element.

5. 30-13 Detection of Radiation
Geiger counter
Scintillation counter
Photo ID

6. Ch 30 TXTHW 30B P