Which zone is the hottest and efficient burning zone of the flame used for casting ?

Related Mcqs:

1. Addition of large amounts of platinum to a casting gold alloy will________________?

   A. Decrease its strength and ability to be hardened
   B. Decrease its tarnish resistance
   C. Increase its fusion temperature
   D. Redden the alloy

2. Gap between true end of casting ring and wax pattern should be______________?

   A. ¼ inch
   B. ½ inch
   C. 3/8 inch
   D. one inch

3. Resistance to corrosion in a cobalt-chrome casting is due to presence of_______________?

   A. High quality iron
   B. Chrome
   C. Cobalt
   D. Nickel

4. Reduction in the fusion temperature of dental gold casting alloys is caused by presence of______________?

   A. Platinum
   B. Copper
   C. Silver
   D. Gold

5. Titanium casting is done_____________?

   A. Under vacuum in argon atmosphere
   B. Under air pressure in nitrogen atmosphere
   C. In specially fabricated aluminium vanadium
   D. Using CAD-CAM technique

6. Fins and spines on the casting is seen due to_______________?

   A. Prolonged heating:
   B. Rapid heating me
   C. Water film contamination
   D. Too high pressure during casting

7. Asbestos liner is used in a casting ring to________________?

   A. Facilitate venting of the mold
   B. Retard the heating of the investment
   C. Permit expansion of the world
   D. All of the above

8. Air bubbles formed on the surface of casting is probably due to________________?

   A. Improper casting pressure
   B. Improper heating of the investment
   C. Improper angulation of sprue
   D. Improper wetting of the wax pattern by the investment

9. The gold alloys used for casting contain at least…. percent of precious metal according to ADA specification number 5________________?

   A. 55
   B. 65
   C. 75
   D. 85

10. Casting shrinkage is compensated by_______________?

    A. Thermal expansion
    B. Hygroscopic expansion
    C. Wax expansion
    D. All of the above