A parallel lead anti-scatter grid consists of bars of height of 1 cm, width of 1 mm, an interspace distance of 5 mm, and covers a field of view of 50 cm. (a) What is the grid ratio? (b) What is the number of lines within the 50 cm grid width? (c) What grid ratio would be needed to ensure that no rays of more than 2 from parallel can pass through the grid unattenuated