211. The solvent flux used for base metal soldering is_______________?

A. Boric acid
A. Borax
B. Fluoride
C. Rouge

212. During soldering, the solidus temperature of the filler material should be_____________?

A. Greater than the substrate material
B. Lesser than the substrate material
C. Equal to the substrate material
D. Temperature not relevant

213. Which of the following increases castability of base metal alloys________________?

A. Tin
B. Beryllium
C. Molybdenum
D. Carbon

214. Which of the following fuel gases used for soldering, has the highest heat content______________?

A. Hydrogen
B. Natural gas
C. Acetylene
D. Propane

215. Binder in phosphate bonded investment is______________?

A. Magnesium oxide & Phosphate
B. Magnesium oxide & Phosphoric acid
C. Magnesium oxide & Monoammonium phosphate
D. Magnesium oxide & Ortho Phosphoric acid

216. Which one of the following elements is NOT added is small amount to be used as grain refiners ?

A. Iridium
B. Ruthinium
C. Indium
D. Platinum

217. Within an hour after cementation of cast gold onlay patient complains of shooting pain every time the teeth comes together Most probable explanation is ______________?

A. Supracocclusion of restoration
B. Retained cement in gingival sulcus
C. Excess acid in mix
D. Galvanic current caused by gold onlay occluding with a large restoration

218. The rate of tarnish and corrosion of class II cast material having VHN 200 is_______________?

A. 0%
B. 2 to 3%
C. 5 to 10%
D. <1%

219. Function of wetting agents used in casting procedure is_________________?

A. To felicitate wetting of ring liner
B. To felicitate mixing investment
C. To reduce contact angle of liquid with max surface
D. For better wax elimination

220. The deoxidizing agent added to dental alloys is______________?

A. Palladium
B. Silver
C. Copper
D. Zinc