(a)  5         3          2         4
    (b)  3         2          4         1
    (c)  3         2          1         4
    (d)  2         3          1         5
Ans: (c)
12. An alloy used in making heating elements for electric heating devices is :
    (a) solder
    (b) alloy steel
    (c) nichrome
    (d) German silver
Ans: (c)
13. The filament of an electric bulb is made of: [CDS 1990]
    (a) iron
    (b) nichrome
    (c) tungsten
    (d) graphite
Ans: (c)
14. Consider the following statements regarding graphite: [CDS 1991]
    1) It is an allotrope of carbon.
    2) It is a good conductor of heat and electricity.
    3) It can be artificially produced.
    Of these statements:
    (a)  1, 2 and 3 are correct
    (b)  1 and 2 are correct
    (c)  1 and 3 are correct
    (d)  2 and 3 are correct
Ans: (a)
15. Carbon, diamond and graphite are together called: [NDA 1993]
    (a) isomers
    (b) allotropes
    (c) isomorphs
    (d) isotopes
Ans: (b)
16. Galvanised iron sheets have a coating of: [CDS 1990]
    (a) tin
    (b) lead
    (c) zinc
    (d) chromium
Ans: (c)
17. Which of the following metals was first discovered by man?
    (a) Bronze
    (b) Silver
    (c) Iron
    (d) Copper
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