1.Which among the following is the characteristics of ceramic? a. High tensile strength b. High coefficient of friction c. More hardness d. All of these 2. What happens when thermosetting polymers are heated? a. They become soft b. They are deformed 3. Select the correct option which shows mechanical property of Metals materials?

1.Which among the following is the characteristics of ceramic? a. High tensile strength b. High coefficient of friction c. More hardness d. All of these 2. What happens when thermosetting polymers are heated? a. They become soft b. They are deformed 3. Select the correct option which shows mechanical property of Metals materials?

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

See similar textbooks

Similar questions

*.Cements are considered as ceramic types -1 a- traditional. b- advanced. *...Ceramics bonding are -2 a- covalent. C- mixed. b- ionic. * Metals are than Ceramics -3 a- harder. b- softer. .Metals have good ductility because -4 b- their low bonding strength. a- their bonds are nondirectional. .. Ceramics are bad electrical conductors because -5 b- they have low electronegativity. a- their valence electrons are restricted.
1. The schematic shown below represents high and low values of which of the following thermal properties of materials? A. Diffusivity B. Conductivity C. Thermal Expansion D. Heat capacity 2. Which one of the following does not represent one of the six families of materials? A. Metals B. Ceramics C. Woods D. Hybrids 3. Which one of the following is not a typical property of a glass? A. High hardness B. Electrically Insulating C. Transparency D. High Toughness 4. Which of the following material properties is most appropriate for describing the stiffness of a material? A. Young's Modulus B. Yield Strength C. Fracture Toughness D. Fatigue Limit 5. The failure of the aircraft wing shown below, when loaded to its design stress, suggests the following about the material it is manufactured from A. Not stiff enough B. Too low a yield strength C. Too low a fracture toughness D. Too high a ductility
Polymeric materials are liable to creep at room temperature, stress and time of loading, which one of the following statements is correct? a. the longer the time, the creep strain increase. b. The higher the temperature, the higher the creep limit. c. Reduce the stress increases the strain. d. Increase the temperature increases the creep strain.
Samples of ceramic insulators are tested for toughness and hardness. The results from 100 samples are summarized as follows: Toughness high low high 71 8 Hardness low 17 4 Find the number of ceramic insulators that satisfies each of the following conditions: a. high hardness and low toughness b. high hardness or low scratch resistance c. low hardness or low scratch resistance
Which of the following is incorrect regarding the degree of crystallinity of semi-crystalline polymers? (This question has more than one correct answer) a. Increasing the degree of crystallinity generally increases polymer strength, elastic modulus and ductility in semi-crystalline polymers b. Semi-crystalline polymers are heat treated to increase the crystallinity and improve polymer strength c. The tendency of a polymer to crystalize decreases with increasing molecular weight d. Heat treatment always results in enhanced polymer strength, elastic modulus and brittleness
Classify each material as a metal, polymer, ceramic or composite based on the properties listed. Brass – Electrically conductive, strong. Magnesium oxide – Electrical and thermal insulator, can resist high temperatures. Plexiglas – Light weight, electrical insulator, cannot withstand large loads. Polychloroprene – Low density, high ductility, not strong, electrical insulator. Boron carbide – High hardness, high stiffness, high toughness.
For an application of high strength components including gears cams and rollers the desired properties in a plastic would be high tensile and impact strength, stability at high temperature, and machine ability. Potential materials which are suitable for these applications are nylon phenolics, TFE filled acetals, PET, and poly carbonate. True or false.
Page 12 of 13 4. Give TWO (2) examples of polymers that can used as a resin in mounting process. 1. 2. 5.Fill in the blank with the following: [grain boundary, dislocation, coarse, stronger] A fine-grained material (one that has small grains) is harder and that is area to impede than one -grained, because the former has a greater total movement. 6. Label ferrite and pearlite in the following photomicrographs of a PCS specimen. 7. Which one is coarser? ANS: (a) Abrasive paper: 180 grit paper or 320 grit paper ANS: (b) Metal specimen: ASTM grain-size number; 4 or 10
In general, polymers have lower strength, hardness, stiffness, density, and temperature resistance compared to ceramics. T or F
Plastics may exhibit a change in properties as they age, particularly when subjected to elevated temperatures. Material properties such as tensile strength will increase with an increasing temperature as a function of increasing time. True or false.
As crystallinity of polymers increases density decreases true or false
* ..In silicates, oxygen atoms which are bonded to two silicon atoms are Nonbridging oxygen (NBOS). Bridging oxygen (BOs). * ..Nonbridging oxygen (NBOS) are formed by Faster cooling of liquid glass. O the addition of either alkali or alkaline earth metal oxides to silica. Ceramics are ........ Organic, nonmetallic, crystalline solids. Inorganic, nonmetallic, crystalline solids Inorganic, nonmetallic, noncrystalline solids.