Constantan is an alloy of copper and _______.

nickel

The correct answer is option 3. nickel.

Constantan is a widely used alloy in electrical applications, known for its low electrical resistance and minimal thermal expansion properties.

Composition: Constantan is primarily composed of copper (Cu) and nickel (Ni). The typical composition of Constantan ranges from approximately 55% copper and 45% nickel to 60% copper and 40% nickel. These proportions may vary slightly depending on the specific application requirements.

Properties: Constantan possesses several advantageous properties that make it suitable for various electrical and electronic applications:

Low Electrical Resistance: Constantan has a relatively high electrical resistivity compared to pure copper, making it useful for resistive elements in electrical circuits, such as resistors and heating elements.

Stability: Constantan exhibits excellent thermal stability and minimal thermal expansion over a wide temperature range. This property ensures consistent performance in applications where temperature changes occur.

Corrosion Resistance: The presence of nickel in Constantan enhances its resistance to corrosion, ensuring durability and longevity, particularly in harsh environments or when exposed to corrosive substances.

Ductility and Malleability: Constantan is ductile and malleable, allowing it to be easily drawn into wires or formed into various shapes to meet specific design requirements.

Applications: Constantan finds widespread use in various electrical and electronic applications, including:

Resistance Wires: Constantan wires are commonly used in resistors, heating elements, and thermocouples due to their stable electrical resistance and predictable temperature coefficient.

Strain Gauges: Constantan foil or wire is employed in strain gauges, devices used to measure mechanical strain or deformation in structures, materials, or components.

Thermocouples: Constantan is often used as one of the conductors in thermocouple pairs, which generate a voltage proportional to temperature differences for temperature measurement purposes.

Electrical Contacts: Constantan is utilized in electrical contacts and connectors for its electrical conductivity and corrosion resistance.

In summary, Constantan is an alloy of copper and nickel known for its favorable electrical, thermal, and mechanical properties. Its composition and characteristics make it well-suited for a wide range of electrical and electronic applications, particularly those requiring stable resistive behavior, durability, and reliability.