Radioactivity is the process by which an unstable atomic nucleus loses energy by radiation. It is measured in becquerels (Bq).
1 rad = 0.01 t½ 
1 t½ = 100 rad 
उदाहरण: 
कन्वर्ट 15 Rad से Half-life:
15 rad = 0.15 t½ 
| Rad | Half-life | 
|---|---|
| 0.01 rad | 0 t½ | 
| 0.1 rad | 0.001 t½ | 
| 1 rad | 0.01 t½ | 
| 2 rad | 0.02 t½ | 
| 3 rad | 0.03 t½ | 
| 5 rad | 0.05 t½ | 
| 10 rad | 0.1 t½ | 
| 20 rad | 0.2 t½ | 
| 30 rad | 0.3 t½ | 
| 40 rad | 0.4 t½ | 
| 50 rad | 0.5 t½ | 
| 60 rad | 0.6 t½ | 
| 70 rad | 0.7 t½ | 
| 80 rad | 0.8 t½ | 
| 90 rad | 0.9 t½ | 
| 100 rad | 1 t½ | 
| 250 rad | 2.5 t½ | 
| 500 rad | 5 t½ | 
| 750 rad | 7.5 t½ | 
| 1000 rad | 10 t½ | 
| 10000 rad | 100 t½ | 
| 100000 rad | 1,000 t½ |