If 16 mAs produce appropriate film density at 72 inches SID,how much mAs is needed at 48 inches SID to maintain that amount of film density?

Question

Quizplus · Accepted Answer

Before actually calculating the answer,it is important to think through that decreasing the SID will require a decrease in mAs to maintain density.Using the mAs/distance compensation formula,mAs₁/mAs₂ = (SID₁)²/(SID₂)²,16/X = 72²/48²,X = 7.1 rounded to 7mAs.

If 16 MAs Produce Appropriate Film Density at 72 Inches