Engineering Materials

11. Admiralty brass used for steam condenser tubes contains copper and zinc in the following ratio

  1. 50 : 50
  2. 30 : 70
  3. 70 : 30
  4. 40 : 60
  5. 60 : 40.

Correct answer: (B)
30 : 70

12. Admiralty gun metal contains

  1. 63 to 67% nickel and 30% copper
  2. 88% copper, 10% tin and rest zinc
  3. alloy of tin, lead and cadmium
  4. iron scrap and zinc
  5. none of the above.

Correct answer: (B)
88% copper, 10% tin and rest zinc

13. Age-hardening is related with

  1. stainless steel
  2. gun metal
  3. german silver
  4. duralumin
  5. 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

  1. 50 : 20 : 20 : 10
  2. 40 : 30 : 20 : 10
  3. 50 : 20 : 10 : 20
  4. 30 : 20 : 30 : 20
  5. 50 : 10 : 20 : 20.

Correct answer: (A)
50 : 20 : 20 : 10

15. Aluminium bronze contains

  1. 94% aluminium, 4% copper and 0.5% Mn, Mg, Si and Fe
  2. 92.5% aluminium, 4% copper, 2% nickel, and 1.5% Mg
  3. 10% aluminium and 90% copper
  4. 90% magnesium and 9% aluminium with some copper
  5. 10% aluminium and 90% tin.

Correct answer: (C)
10% aluminium and 90% copper

16. Aluminium bronze contains aluminium and copper in the ratio of

  1. 50 : 50
  2. 40 : 60
  3. 60 : 40
  4. 10 : 90
  5. 90 : 10.

Correct answer: (D)
10 : 90

17. Amorphous material is one

  1. in which atoms align themselves in a geometric pattern upon solidification
  2. in which there is no definite atomic structure and atoms exist in a random pattern just as in a liquid
  3. which is not attacked by phosphorous
  4. which emits fumes on melting
  5. 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

  1. cast iron
  2. forged steel
  3. mild steel
  4. high carbon steel
  5. H.S.S.

Correct answer: (D)
high carbon steel

19. An example of amorphous material is

  1. zinc
  2. lead
  3. silver
  4. glass
  5. brass.

Correct answer: (D)
glass

20. An important property of high silicon (12 - 18%) cast iron is the high

  1. tenacity
  2. brittleness
  3. plasticity
  4. corrosion resistance
  5. hardness.

Correct answer: (E)
hardness.

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