221. Which of the following is function of fluoride flux in soldering process ?
A. It prevents the formation of copper oxide
B. It prevents the formation of chromium oxide or dissolves chromic oxide layer
C. It prevents the flow of material in undesirable area
D. Increase the strength of solder
222. Percentage of gold in high noble alloy is______________?
A. N 25%
223. Gases dissolved in molten metals are liberated when cooled giving rise to________________?
A. Suckback porosity
B. Gas inclusion porosity
C. Localized shrinkage porosity
224. Casting flux is used to_______________?
A. Prevent the oxidation of the metal during melting
B. increase the melting point of the flux
C. Flaring the point of the sprue attachment
D. None of the above
225. The main ingredient of inlay wax is__________________?
A. Candellila wax
B. Paraffin wax
C. Carnauba wax
D. Gum dammar
226. Who was the first person to introduce cast inlay restoration into dentistry ?
A. William H Taggart
C. G.V. Black
227. Disadvantage of having a short sprue is________________?
A. Rapid solidification of metal
B. No place for reservoirs
C. Incomplete evacuation of gases
D. Difficulty in removing casting from investment
228. 18-B Stainless steel orthodontic wire has_______________?
A. 18% Nickel 8% Chrominum
B. 18% Chromium 8% Nickel
C. 18% Chromium 8% Cobalt
D. 18% Carbon 8% Iron
229. Inlay wax is used to_______________?
A. Temporarily cement inlays:
B. Make inlay wax patterns
C. Invest inlay patterns
D. Box models
230. Quartz in investment material is added for_______________?
B. Expansion components for casting shrinkage
C. Decrease strength
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PLEASE COMMENT WITH CORRECT ANSWER AND ITS DETAIL EXPLANATION IN COMMENT BOX.