A circular lead lined device that slides onto the tube head is ...

[beccaep]

A circular lead lined device that slides onto the tube head is a(n):
 
 aperture diaphragm
  wedge filter
  collimator
  extension cone

Question 2

Which phase of processing is highly dependent on its temperature in order for it to be effective?
 
 fixer
  developer
  washing
  drying

[tsternbergh47]

Answer to Question 1

extension cone

Rationale: Extension cones attach to the tube head. Cones may be cylinder or flare type. Extension cones are able to telescope out and come in different diameters to alter the field size.

Answer to Question 2

developer

Rationale: The developer temperature is typically set 93-95 degrees Fahrenheit. This temperature directly effects the activity of the solution. Increases or decreases of developer solution can alter the density on the image. Increased temperatures will result in increased density and decreased temperatures will result in decreased density.

[beccaep]

Thanks for the timely response, appreciate it

[phuda]

Great answer, keep it coming