41 __ is an example of background radiation. a. Terrestrial b. Cosmic c. Artificial d. Both a b A B c D 42. One rem is equal to __ sieverts. a. 0.01 sv b. 15V c. 0.1 sv A B C 43. The use of the F-speed film instead of D-speed film reduces the absorbed dose by __ a. 10 b. 25 c. 50 d. 60 A B