Question 12
(a) State two applications of radioactivity in the field of agriculture.
[2 marks]
(b) The table below provides information on the decay of a radioactive material.
Time/min |
0 |
20 |
40 |
60 |
80 |
100 |
120 |
140 |
Count rate/min-1 |
21000 |
9300 |
4300 |
2000 |
1300 |
1000 |
830 |
660 |
(i) Plot a graph of count rate on the vertical axis and time on the horizontal axis.
[use the graph sheet provided on page 15 and the graph should be a smooth curve through the points]
Observation
(a) Application of radioactivity in agriculture
- Food preservation.
- Safe application of fertilizer.
- Improving crop varieties.
- Eradication of insects and pests
(b) (i) Graph
- Both axes correctly distinguished (Award ½ mark each)
- Reasonable scale
- Eight points correctly plotted
(ii) Determination of half-life
Line for determining half-life correctly shown on graph
Half-life correctly recorded
