Q1: __________ has a negative co-efficient of linear expansion.

ANS:B - Copper

Copper is a metallic element with the chemical symbol Cu and atomic number 29. It is well-known for its distinctive reddish-brown color and excellent electrical and thermal conductivity. Here's an explanation of some key aspects of copper:

1. Physical Properties: Copper is a ductile and malleable metal, meaning it can be easily shaped and formed into various objects. It has a relatively high melting point of 1,984 degrees Fahrenheit (1,085 degrees Celsius) and a density of 8.96 grams per cubic centimeter.
2. Electrical Conductivity: Copper is one of the best conductors of electricity among all metals. It exhibits excellent electrical conductivity, surpassed only by silver. This property makes copper highly desirable for electrical wiring, circuits, and electrical components in various applications, including power transmission, electronics, and telecommunications.
3. Thermal Conductivity: In addition to its exceptional electrical conductivity, copper also possesses excellent thermal conductivity. It efficiently conducts heat, making it suitable for use in heat exchangers, cooling systems, and cookware.
4. Corrosion Resistance: Copper has good corrosion resistance, particularly in atmospheric and aqueous environments. When exposed to air, copper forms a thin layer of oxide (patina) on its surface, which acts as a protective barrier against further corrosion. This property makes copper suitable for outdoor applications and architectural uses.
5. Alloys: Copper is often alloyed with other metals to enhance its properties. Some common copper alloys include brass (copper-zinc alloy), bronze (copper-tin alloy), and cupronickel (copper-nickel alloy). These alloys exhibit a wide range of properties and are used in various industries, including manufacturing, construction, and marine applications.
6. Biological Role: Copper is an essential trace element for living organisms. It plays a crucial role in various biological processes, including enzyme function, iron metabolism, and the formation of connective tissues. However, excessive exposure to copper can be toxic to humans and other organisms.

Overall, copper is a versatile metal with a wide range of applications due to its excellent electrical and thermal conductivity, corrosion resistance, and malleability. Its unique combination of properties makes it indispensable in modern technology, industry, and everyday life.