Physics (Essay) Paper 2 WASSCE (PC 2ND), 2022

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