302-L2-MOCK

What is the primary difference between ferrous and non-ferrous metals?

• Magnetic properties

• Colour and texture

• Density and weight

• Electrical conductivity

Answer explanation

The primary difference between ferrous and non-ferrous metals is their magnetic properties. Ferrous metals, like iron, are magnetic, while non-ferrous metals, such as aluminum and copper, are not.

How does carbon content affect the properties of steel?

• Increases electrical conductivity

• Decreases hardness

• Increases strength

• Decreases corrosion resistance

Answer explanation

Increasing carbon content in steel enhances its strength due to the formation of harder microstructures. This makes steel more durable and suitable for various applications, while other properties like corrosion resistance may be affected.

Which heat treatment process is used to soften steel?

• Hardening

• Tempering

• Annealing

• Normalising

Answer explanation

Annealing is the heat treatment process used to soften steel by heating it to a specific temperature and then allowing it to cool slowly. This process reduces hardness and increases ductility, making it easier to work with.

What is a common cause of galvanic corrosion?

• High temperature

• Contact with dissimilar metals

• Exposure to sunlight

• High humidity

Answer explanation

Galvanic corrosion occurs when two dissimilar metals are in contact in the presence of an electrolyte, leading to an electrochemical reaction. This makes 'Contact with dissimilar metals' the correct answer.

Which material is best suited for high-temperature applications?

• Aluminium

• Copper

• Stainless steel

• Plastic

Answer explanation

Stainless steel is best suited for high-temperature applications due to its excellent strength and resistance to oxidation and corrosion at elevated temperatures, unlike aluminium, copper, or plastic.

What is the primary purpose of tempering steel?

• Increase hardness

• Reduce brittleness

• Improve colour

• Enhance magnetic properties

Answer explanation

The primary purpose of tempering steel is to reduce brittleness. This process involves heating the steel to a specific temperature and then cooling it, which helps to improve its toughness while maintaining a balance of hardness.

Which of the following is a non-destructive testing method?

• Tensile test

• Radiography

• Hardness test

• Creep test

Answer explanation

Radiography is a non-destructive testing method that uses X-rays or gamma rays to inspect the internal structure of materials without causing damage. In contrast, tensile, hardness, and creep tests are destructive methods.

What is the main advantage of using composites in engineering?

• High density

• Low cost

• High strength-to-weight ratio

• Magnetic properties

Answer explanation

The main advantage of using composites in engineering is their high strength-to-weight ratio, which allows for lightweight structures without sacrificing strength, making them ideal for various applications.

Which material is known for its excellent electrical insulation properties?

• Copper

• Aluminium

• Plastic

• Steel

Answer explanation

Plastic is known for its excellent electrical insulation properties, making it ideal for protecting electrical components. In contrast, copper, aluminium, and steel are conductive materials and do not provide insulation.

What is the effect of alloying elements on low alloy steels?

• Decrease in strength

• Increase in corrosion resistance

• Decrease in thermal stability

• Increase in weight

Answer explanation

Alloying elements in low alloy steels enhance properties such as corrosion resistance. This is crucial for applications in harsh environments, making the correct choice 'Increase in corrosion resistance'.