Which pair of metals exhibits the highest electrical and thermal conductivities for engineering applications?
Copper and aluminium
The question asks which pair combines the highest electrical and thermal conductivities among metals used in engineering.
Conductivity depends on how freely electrons move through the metal lattice, and among affordable engineering metals a small group stands well above the rest.
Copper has outstanding electrical and thermal conductivity, bettered only by silver, which makes it the first choice for wiring, busbars and heat exchangers.
Aluminium is the next widely used high-conductivity metal; it conducts somewhat less than copper but is far lighter and cheaper, so it is used for overhead lines, heat sinks and radiators.
Cast iron and wrought iron, and the mild and stainless steels, are ferrous metals whose conductivity is many times lower than copper's, so those pairs cannot lead.
Lead is a poor conductor and bronze, being a copper alloy, conducts less than pure copper, so that pair also falls short of copper and aluminium.
Hence, the answer is Copper and aluminium.
In Stress & Strain diagram, stress is always represented on the ______.
Alumina is prepared from ______.
Ferrous metals generally contain major amounts of:
In which situation would wrought iron be a better choice than cast iron?
In general, resistivity of an alloy ______ its constituent metals.
In Stress & Strain diagram, stress is always represented on the ______.
Which of the following statements about the resistivity of metals is INCORRECT?
Aluminium in its pure form is not used for engineering work because
The ability of a metal to withstand shock and impact