MTE Final Concepts

Temperature

Which does not influence the linear coefficient of thermal expansion?

True

Is it possible that the ceramic cpating might fracture during heating due to thermal stresses in the coating?

Polymers

Which family of materials exhibits the lowest values of thermal conductivity?

Lattice vibrations

What is responsible for heat conduction in ceramics?

True

The electrical resistivity of a material is dependent on its microstructure.

Conductors, semiconductors, insulators

Based of electrical conductivity values, materials are classified as…

Insulators

Which of the following gases, in general, has highest band gap energy?

Temperature and compositions

Which would affect the electrical conductivity of metals &alloys?

Mobility

With increase in temperature, electrical conductivity decreases due to a decrease in…

Number of charged carriers

With an increase in solute content, the electrical conductivity of alloys decreases. This is due to a decrease in ............................ with an increase in solute content.

Increases

The electrical conductivity of semiconductors ...................... with an increase in temperature.

Number of charged carriers

With an increase in temperature, the electrical conductivity of semiconductors increases. This is due to an increase in ............................ with an increase in temperature.

None

Which from the following is not a type of mechanical property?

Rockwell hardness test

Between Rockwell hardness test and Brinell hardness test, which is more popular test?

Fatigue

Which from the following represents cyclic nature of loading on engineering components?

Ferrous alloys

Which from the following will exhibit endurance limit in S-N curve?

Time dependent

Creep is a ............................ plastic deformation

Yes

There are three stages of creep - primary creep, secondary creep, and tertiary creep. The creep-rate corresponding to secondary creep rate is termed as secondary creep rate, steady-state creep-rate or minimum creep-rate. Does it depend on applied stress and temperature?

Brittle material

A material under monotonic tensile loading fractures abruptly without much plastic deformation. This is a…

High reflectivity

You have to select a new material for designing a mirror to be used in a telescope. What optical properties would you consider from the following?

E>Eg

To prevent transmission of photons with energy E through a semiconductor with band gap energy Eg, you will select a semiconductor material such that…

Refraction, transmission, reflection, absorption

Which from below is/are type(s) of optical phenomenon/phenomena?