Engineering Materials

11. Addition of silicon to aluminium results in

1. improvement of casting characteristics
2. improvement of corrosion resistance
3. one of the best known age and precipitation-hardening systems
4. improving machinability
5. none of the above.

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

1. 50:50:00
2. 30 : 70
3. 70:30:00
4. 40 : 60
5. 60:40:00

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13. 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.

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14. Age-hardening is related with

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

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15. 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.

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16. 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.

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

1. 50:50:00
2. 40 : 60
3. 60:40:00
4. 10 : 90
5. 90:10:00

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18. 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.

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19. An engineer’s hammer is made of

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

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20. An example of amorphous material is

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

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