Barriers that will provide protection from the useful beam are: ...

[tiffannnnyyyyyy]

Barriers that will provide protection from the useful beam are:
 
 control area
  control booth
  secondary barrier
  primary barrier

Question 2

The amount of distance between a part and the image receptor is known as:
 
 source-to-object distance
  source-to-image distance
  object-to-image distance
  exposure index

[31809pancho]

Answer to Question 1

primary barrier

Rationale: Primary barriers protect from the useful beam. Primary barriers are any surface that may be struck by the beam, including lead walls and doors.

Answer to Question 2

object-to-image distance

Rationale: Object-to-image receptor distance is OID. Increased OID contributes to part magnification which is destructive to image detail. The general rule is to maintain the part as close to the IR as possible.

[tiffannnnyyyyyy]

Thanks for the timely response, appreciate it

[bassamabas]

Great answer, keep it coming