A Rose model phantom shown below (a plastic wedge with a series of drilled holes) can be used to generate contrast detail curve. Assume hole A is 5 cm thick, the wedge has a of 1 cm-1 , and the holes has a of 0 cm-1 . Find the contrast of hole A in a radiographic image when X-ray is parallel to the length of the holes. Explain how you can find the contrast resolution of an X-ray imaging system with this phantom