Q.1
Brass is an alloy of 70 per cent copper and 30 per cent zinc. Which of the following is a use of brass?
  • In electrical fittings
  • In boat fittings
  • In aircraft frames
  • In musical instruments
Q.2
Why does iron directly from a blast furnace have limited usefulness?
  • It is too hot
  • It is in the form of a big ingot
  • It contains about 4% impurities, including carbon
  • It is too soft
Q.3
Aluminium is a light metal but why is it not used to make aircraft?
  • It is too brittle
  • It corrodes too easily
  • It is too weak
  • It conducts electricity
Q.4
What is an alloy?
  • A mixture of metals
  • A mixture of non-metals
  • A mixture of a metal with either non-metals or other metals
  • A pure metal that has been shaped in a certain way
Q.5
Which of the following is a use of ?
  • Boat fittings
  • Aircraft body panels
  • Cables for large cranes
  • All of the above
Q.6
How is the percentage of carbon in pig iron reduced to form steels?
  • By burning it off using oxygen
  • By filtering it out
  • By dissolving it in sulfuric acid
  • By scraping it off the surface of the metal
Q.7
Which of the following is a reason for making an alloy?
  • To make a material that is transparent to light waves
  • To make a corrosion resistant material
  • To make a harder material
  • To make a more malleable material
Q.8
Why are alloys stronger than the materials from which they are made?
  • They contain different sized atoms that 'lock' the structure
  • This is only true if you use a strong metal with a weak one
  • They form a chemical compound
  • The heat needed to make them gives alloys their greater strength
Q.9
Why are 'silver' coins made from an alloy or nickel plated steel and not from silver?
  • Silver is too valuable
  • People would keep silver coins instead of spending them
  • It is too difficult to get silver into the right size and shape
  • Silver is too soft
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