Radiology General 3321de30 At 90 kVp and 15 mA at a source film distance of 8 inches, the exposure time for a film is ½ second, using the same amount of kVp and mA, the exposure time at 16 inches is: A ½ second B 1.5 second C 1 second D 2 seconds High-Yield Explanation No explanation provided.