Element X which has initial activity R0 and radiation intensity In is used as a medium for tracking water pipe leaks in the soil. If the detector at ground level records a 25% change in radiation intensity at the site of the leak, (I). Determine the depth of the pipe if it is known that the attenuation coefcient of the soil layer is 111111 , (ll). Explain whether the magnitude of the activity of element X is affected by the medium in which the element is occurs