66. What is the process of joining two metal pieces together by heating them and applying a filler metal with a lower melting point called?
a) Casting
b) Welding
c) Soldering
d) Brazing
67. Which metal is commonly used for making electrical contacts and connectors in high-temperature environments due to its high melting point?
a) Copper
b) Aluminum
c) Silver
d) Tungsten
68. What is the process of converting iron into wrought iron or steel by removing impurities through repeated heating and hammering called?
a) Refining
b) Smelting
c) Milling
d) Puddling
69. Which metal is primarily used for making electrical power cables and wires due to its low resistance and cost-effectiveness?
a) Copper
b) Aluminum
c) Iron
d) Silver
70. What is the process of joining two metal pieces together by melting and solidifying the base metal itself without the use of a filler material called?
a) Casting
b) Welding
c) Soldering
d) Fusion
