what minimum total amount of filtration (inherent plus added) is required in x-ray equipment operated above 70 KVP:
a. 2.5 mm AL equivalent
b. 3.5 mm AL equivalent
a. 2.5 mm CU equivalent
a. 3.5 mm CU equivalent
a. 2.5 mm AL equivalent
b. 3.5 mm AL equivalent
a. 2.5 mm CU equivalent
a. 3.5 mm CU equivalent