Engineering Materials
11. Admiralty brass used for steam condenser tubes contains copper and zinc in the following ratio
- 50 : 50
- 30 : 70
- 70 : 30
- 40 : 60
- 60 : 40.
Correct answer: (B)
30 : 70
12. Admiralty gun metal contains
- 63 to 67% nickel and 30% copper
- 88% copper, 10% tin and rest zinc
- alloy of tin, lead and cadmium
- iron scrap and zinc
- none of the above.
Correct answer: (B)
88% copper, 10% tin and rest zinc
13. Age-hardening is related with
- stainless steel
- gun metal
- german silver
- duralumin
- cast iron.
Correct answer: (D)
duralumin
14. Alnico, an alloy used extensively for permanent magnets contains iron, nickel, aluminium and cobalt in the following ratio
- 50 : 20 : 20 : 10
- 40 : 30 : 20 : 10
- 50 : 20 : 10 : 20
- 30 : 20 : 30 : 20
- 50 : 10 : 20 : 20.
Correct answer: (A)
50 : 20 : 20 : 10
15. Aluminium bronze contains
- 94% aluminium, 4% copper and 0.5% Mn, Mg, Si and Fe
- 92.5% aluminium, 4% copper, 2% nickel, and 1.5% Mg
- 10% aluminium and 90% copper
- 90% magnesium and 9% aluminium with some copper
- 10% aluminium and 90% tin.
Correct answer: (C)
10% aluminium and 90% copper
16. Aluminium bronze contains aluminium and copper in the ratio of
- 50 : 50
- 40 : 60
- 60 : 40
- 10 : 90
- 90 : 10.
Correct answer: (D)
10 : 90
17. Amorphous material is one
- in which atoms align themselves in a geometric pattern upon solidification
- in which there is no definite atomic structure and atoms exist in a random pattern just as in a liquid
- which is not attacked by phosphorous
- which emits fumes on melting
- none of the above.
Correct answer: (B)
in which there is no definite atomic structure and atoms exist in a random pattern just as in a liquid
18. An engineer's hammer is made of
- cast iron
- forged steel
- mild steel
- high carbon steel
- H.S.S.
Correct answer: (D)
high carbon steel
19. An example of amorphous material is
- zinc
- lead
- silver
- glass
- brass.
20. An important property of high silicon (12 - 18%) cast iron is the high
- tenacity
- brittleness
- plasticity
- corrosion resistance
- hardness.
Correct answer: (E)
hardness.