CAP 3 Materiales

Question 1

1. The mass of an engineering material per unit of volume (kg/m3 or lb/ft3) is also known as:
   a. viscosity.
   b. density.
   c. volume.
   d. área.

Answer 1

b. density.

Question 2

2. The thermal energy required to raise the temperature of a unit mass by one degree measure by celsius (°C), kelvin (K), or Fahrenheit (°F) is known as.
   a. applied heat.
   b. melting point.
   c. specific heat.
   d. dispersal point.

Answer 2

c. specific heat.

Question 3

3. The quantity of heat transmitted per unit area by a material of a given thickness and temperature gradient is known as:
   a. thermal transmission.
   b. thermal gradient.
   c. thermal absorption.
   d. thermal conductivity.

Answer 3

d. thermal conductivity.

Question 4

4. In general. materials with high melting
   temperatures and strong bonds between atoms
   have a _________than materials with lower
   melting points and weaker bonds between atoms.

a. lower coefficient of thermal expansion
b. higher coefficient of thermal expansion
c. Stronger coefficient of thermal expansion
d. weaker coefficient of thermal expansion

Answer 4

a. lower coefficient of thermal expansion

Question 5

5. Electrical conductivity is an expression of how
   well materials conduct electrical current.
   Materials that can conduct electricity under
   certain circumstances and not others are called:
   a. conductors .
   b. resistors.
   c. semiconductors .
   d. súper conductors .

Answer 5

c. semiconductors .

Question 6

6. Electrical conductivity is an expression of how
   well materials conduct electrical current.
   Materials that are covalently bonded where the
   electrons are not free to move about to conduct
   electricity are called:
   a. conductors.
   b. resistors.
   c. semiconductors.
   d. super conductors.

Answer 6

b. resistors.

Question 7

7. Materials that exhibit a strong attraction to magnetic fields and are able to retain their magnetic properties even after the magnetic field has been removed are referred to as;

a. diamagnetic.
b. paramagnetic.
c. ferromagnetic.
d. anti-ferromagnetic

Answer 7

c. ferromagnetic.

Question 8

8. Which of the following materials is considered to be diamagnetic?
   a. Iron.
   b. Stainless steel.
   c. Copper.
   d. Molibdenum.

Answer 8

c. Copper.

Question 9

9. Material that is dear and allows light to pass through is considered:

a. filtering.
b. opaque.
c. translucent.
d. transparent.

Answer 9

d. transparent.

Question 10

10. Material that is cloudy and only allows part of the light to pass through is considered:

a. filtering.
b. opaque.
c. translucent.
d. transparent.

Answer 10

c. translucent.

Question 11

11. Material that does not allow light to pass through is considered:

a. filtering.
b. opaque.
c. translucent.
d. transparent.

Answer 11

b. opaque.

Question 12

12. The optical properties of a material refer to the response of the material to electromagnetic radiation, particularly:

a. radio waves.
b. infrared.
c. visible light.
d. X-rays.

Answer 12

c. visible light.

Question 13

13. Metals are transparent to high-end frequencies of the electromagnetic spectrum, including which of the following?
    a. Radio waves.
    b. Infrared.
    c. Visible light.
    d. X-rays.

Answer 13

d. X-rays.

Question 14

14. When an applied load does not exceed yield strength of the material and the material returns to its original configuration after the load is removed, this is known as:

a. plastic deformation.
b. elastic deformation.
c. spring back.
d. resting state.

Answer 14

b. elastic deformation.

Question 15

15. When a load exceeds the yield strength of the material and the material does not return to its original configuration after the load is removed, this is known as:
    a. plastic deformation.
    b. elastic deformation .
    c. spring back.
    d. resting state.

Answer 15

a. plastic deformation.

Question 16

16. One of the most common tests for evaluating the strength of a material is the:

a. brinell hardness test.
b. charpy impact test.
c. tensile test.
d. micro-hardness test.

Answer 16

c. tensile test.

Question 17

17. The maximum energy that can be absorbed per
    unit volume without creating a permanent
    distortion is known as:
    a. tensile strength.
    b. ultimate tensile strength.
    c. modulus of elasticity.
    d. modulus of resilience.

Answer 17

d. modulus of resilience.

Question 18

18. What material property is measured that is
    indicative of a material’s ability to resist
    permanent deformation or penetration with an
    indenter under load?
    a. Tensile strength.
    b. Brittleness.
    c. Toughness.
    d. Hardness.

Answer 18

d. Hardness.

Question 19

19. Vickers, knoop, rockwell, and brinell are all
    examples of what type of material property test?
    a. Tensile.
    b. Impact.
    c. Hardness.
    d. Toughness.

Answer 19

c. Hardness.

Question 20

20. The initiation of cracks at nucleation points,
    such as stress concentration points or
    inclusions, which begin to grow under cyclic
    loading until they are large enough to cause
    failure of a material, is called:
    a. fatigue.
    b. tensión.
    c. compression.
    d. creep.

Answer 20

a. fatigue.