421. Water powder ratio of dental stone and plaster is respectively_________________?

A. 0.28 and 0.6
B. 0.6 and 0.28
C. 0.6 and 3.2
D. 0.28 and 0.98

422. Model plaster (white) used to cast study models before mixing with water, is largely composed of____________?

A. CaO
B. CaCO3
C. (CaSO4)2-½H2O
D. CaSO4-2H2O

423. White gold alloy predominantly is______________?

A. Gold added with palladium
B. Gold added with calcium
C. Gold with much of chromium
D. Gold with silver

424. In type II gold alloys _______ Karat gold is used?

A. 24 K
B. 22 K
C. 18 K
D. 10 K

425. The material used in its pure form in dentistry is______________?

A. Composite
B. Silver
C. Gold
D. Amalgam

426. Cohesion of gold foil is an example of______________?

A. Atomic attraction and welding
B. Annealing
C. Wedging
D. Adaptation

427. Average particle size of powdered gold is________________?

A. 10 um
B. 15 um
C. 30 um
D. 0.1 um

428. The pure form of gold used in dentistry is known as___________________?

A. Cohesive gold
B. Non cohesive gold
C. Class I casting gold
D. Class IV casting gold

429. Electralloy is an alloy of________________?

A. Gold and Platinum
B. Cobalt and Chromium
C. Gold and Calcium
D. Tin and chromium

430. The carat for Au foil used for restorations is_______________?

A. 18
B. 20
C. 22
D. 24