This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
Thickness of lead apron to prevent radiation – 
Select and explain. 
A. 1mm, B. 3mm, C. 0.5mm, D. 7mm
C: 0.5mm
Answer: C: 0.5mm 
Explanation: Lead aprons (0.5mm of lead) will reduce the intensity of scattered X-ray over 90% and should be worn by all workers regularIy associated with x-ray procedures.