31. Which metal is commonly used for making electrical contacts and connectors in high-temperature and corrosive environments?
a) Copper
b) Aluminum
c) Silver
d) Nickel
32. What is the process of removing impurities from a metal by passing an electric current through it called?
a) Electroplating
b) Electrorefining
c) Electrowinning
d) Electromachining
33. Which metal is primarily used for making magnets due to its strong magnetic properties?
a) Copper
b) Aluminum
c) Iron
d) Nickel
34. What is the process of separating metal ions from a solution using an electric current called?
a) Electroplating
b) Electrorefining
c) Electrowinning
d) Electromachining
35. Which metal is commonly used for making pipes, fittings, and water distribution systems due to its corrosion resistance?
a) Copper
b) Aluminum
c) Iron
d) Stainless steel
