Gamma rays are passed through a lead absorber of thickness x. The gamma count rate is measured by a detector. Figure 2 shows the apparatus used.

Plot, on Figure 3, a graph of In(C/ counts s¹) against .x.

Determine μ. State an appropriate unit for your answer. Show that Co is approximately 5000 counts s™¹. 5 Determine the thickness of lead that will reduce C to a value equal to212 markel