A. Increase the strength
B. Counter balance contraction of gypsum during heating
C. aid in hygroscopic expansion
D. Increase the shelf life of investment
Related Mcqs:
- Gypsum bonded investment should not be heated over______________?
A. 700°C
B. 1,300°C
C. 1,063°C
D. 900°C - The best pickling solution for gypsum bonded investment is_______________?
A. Hydrochloric acid
B. Nitric acid
C. Sulphuric acid
D. Phosphoric acid - A thinner mix of a gypsum bonded investment will_______________?
A. Produce a smoother casting
B. Decrease setting expansion
C. Increase setting expansion
D. Increase thermal expansion - Quartz in investment material is added for_______________?
A. Strength
B. Expansion components for casting shrinkage
C. Decrease strength
D. Contraction - The product, which is obtained by calcining gypsum under steam pressure at 120-130°C or by dehydrating gypsum in the presence of sodium succinate is_______________?
A. Alpha – hemihydrates
B. Beta – hemihydrates
C. Calcium sulphate dihydrate
D. Orthorhombic anhydrate - 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 - Binder used in Gypsum investment is_________________?
A. Silica
B. Quartz
C. Cristobolite
D. Calcium sulphate monohydrate - The strength of a gypsum investment is dependent on_______________?
A. Carbon content
B. Silica content
C. Gypsum
D. Copper - Modiffiers are added to gypsum mainly to_______________?
A. Modify setting time
B. Modify setting expansion
C. Modify strength
D. Decrease the porosity - Lenolin is added is ZOE paste to______________?
A. Decrease flow
B. Increase flow
C. Accelerate reaction
D. Decrease irritation due to eugenol
