FREE Bachelor of Mechanical Engineering Materials Science Questions and Answers
A given element's many isotopes all share the same:
The molar mass of an element varies because different isotopes have different numbers of neutrons but the same number of protons. Additionally, it alters the p-n ratio, making one isotope more stable than the other. For instance, tritium is radioactive but protium is stable.
Degenerate energy levels in the wave-mechanical model of an atom have:
Energy levels that are degenerate are equivalent. When there is no external magnetic field, the orbitals in the same subshell of an atom degenerate.
What is the dislocation in which Burgers vector and line direction are neither parallel nor perpendicular?
Mixed dislocations are those that have both screw and edge dislocation characteristics, with the line direction and burger vector being parallel in screw dislocation and perpendicular in edge dislocation, respectively. Burgers vector and line direction thereby form an angle that is neither perpendicular nor parallel.
Which of the following attributes does metal have an advantage over ceramic in?
In general, ceramics have greater or equal toughness, yield strength, and hardness, but they are quite prone to plastic deformation. Any tension above their yield point causes fracture, no matter how slight.
A great refractory material is ceramic. A substance is referred to as refractory if it:
Furnaces typically have ceramic linings because these materials, which mostly consist of oxides, carbides, and nitrides, can sustain extremely high temperatures.
Which one of the following does not represent a pure form of matter?
Both an element and a compound are regarded as pure forms of matter since different samples of the same element or compound will have the exact same makeup.
Argon has an isobar of calcium. They vary in:
Proton and neutron counts vary between isobars, while the overall amount of nucleons (protons and neutrons) is constant across all isobars. Isobars therefore share the same atomic weight.
Which of the following is not a biomaterial?
Bio-materials must be compatible with the bodily tissues and non-toxic because they are implanted into living organisms to replace damaged portions. All of the aforementioned materials—metals, ceramics, polymers, and their mixtures—can be employed as biomaterials as long as these requirements are satisfied.
A significant composite is GFRP. It represents
Fiberglass, also known as glass fiber reinforced polymer (GFRP), is a lightweight, highly durable, and corrosion-resistant industrial material.
The value of one unified atomic mass unit is .
1 amu is equal to 1/12 of the atomic mass of carbon, 1/16 of the atomic mass of oxygen, and 1/2 of the mass of hydrogen molecules (not molar).
Which of the following contains the fewest atoms?
Any gas has an Avogadro number of atoms or molecules per gram-mole. As a result, one gram-mole of hydrogen gas and one gram-mole of helium gas, respectively, weigh two and three grams. 1g He equals 1/3 g-mol He and 1g H2 equals 1/2 g-mol H2. Helium therefore has the fewest atoms per gram.
What statement about polymers is accurate?
Polymeric molecules have a high molecular mass and are collections of many monomer units. As the stress created is not directly proportional to deformation, Hooke's law typically does not apply to polymers. Because polymers have low densities, their strength to mass ratio frequently rivals that of metals and ceramics.
Iron and carbon are the basic components of steels. Which of the aforementioned subgroups do they belong ?
Steels are regarded as iron alloys because they typically contain less than 6% carbon, making them metallic solids.
A species' atomic number is the sum of its:
The characteristic that sets apart atoms of one species from another is the atomic number, or the total number of protons. Hydrogen and helium, for instance, have atomic numbers of 1 and 2, respectively.
The following terms describe species that have various numbers of protons but the same number of neutrons:
Atoms of several elements that have the same number of neutrons but differing atomic and mass numbers are said to be isotones. For instance, the isotones of boron-12 and carbon-12 both have 7 neutrons.
What kind of dislocation inserts an extra plane into the crystal?
A second half plane of atoms in a lattice is all that is needed to represent the edge defect. Because there are so many defective sites generated within the lattice along a line, the dislocations are known as a line defect. This sort of defect adds an additional atomic plane inside the crystal.