This set of Physical Chemistry Multiple Choice Questions & Answers (MCQs) focuses on “Hydrogen Bonds, Hybrid Orbitals, and Band Theory of Solids – Set 3”.
1. Which of the following energy band is occupied by the valence electrons?
a) Electrons band
b) Valence band
c) Conduction band
d) Forbidden band
View Answer
Explanation: The valence electrons reside in valence shell. The valence shell is also know as valence band. The valence band is created when the electrons get excite and move to the another band called conduction band.
2. What is the name given to the materials that undergo plastic deformation before breaking?
a) Brittle
b) Amorphous
c) Ductile
d) Polymers
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Explanation: Ductility is characterized by a material’s ability to deform plastically without failure under compressive stress. Thus, substances that elongate considerably and undergo plastic deformation before they break are known as ductile substances.
3. Which of the following is known by the formation of large molecules by joining small molecules?
a) Fusion
b) Crystallization
c) Subtraction
d) Polymerization
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Explanation: Polymerization refers to the joining together of smaller molecules to form a larger molecule. These small molecules are usually known as monomers. Monomers combine chemically to produce a very large chain-like or network molecule called a polymer.
4. Which of the following name is given to any alteration produced in shapes length or volume when a body is subjected to some external force?
a) Deformation
b) Extension
c) Toughness
d) Stiffness
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Explanation: Deformation is any process that affects the shape, size, or volume of an area of the material when the material is subjected to some external force. Deformation has two types, permanent deformation and temporary deformation.
5. How does the ferromagnet get magnetized?
a) At low AC voltage
b) At high DC voltage
c) A.C voltage at its peak
d) 300 Volts
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Explanation: The ferromagnet becomes fully magnetized when the alternating current is at its peak value. When the alternating current is at its positive peak value, it fully magnetizes the specimen in one direction and when the current is at its negative peak, it fully magnetizes it in the opposite direction.
6. Which of the following is a curie temperature?
a) At which semi-conductors become conductors
b) At which paramagnetic becomes diamagnetic
c) At which metals become super conductors
d) At which ferromagnetic becomes paramagnetic
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Explanation: Curie temperature is the temperature at which certain materials lose their permanent magnetic properties, to be replaced by induced magnetism. When a magnet material is heated to a very high temperature, it loses its magnetic properties. And hence, ferromagnetic becomes paramagnetic.
7. Which of the following substances has the highest elasticity?
a) Steel
b) Rubber
c) Glass
d) Copper
View Answer
Explanation: The strain and stress that are produced in the material steel is normally smaller than the strain obtained in case of rubber. Thus, it is concluded that steel has the highest elasticity and we determine this on the basis of Young’s modulus.
8. What is the SI unit of modulus of elasticity of substance?
a) Nm-2
b) Nm-1
c) Jm-2
d) Dimensionless
View Answer
Explanation: An elastic modulus (also known as modulus of elasticity) is a quantity that measures an object or substance’s resistance to being deformed elastically when a stress is applied to it. The SI unit of modulus of elasticity of substance is Nm-2.
9. Which one of the following physical quantities does not have the dimensions of force per unit area?
a) Stress
b) Strain
c) Young’s modulus
d) Pressure
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Explanation: Strain does not have the dimensions of force per unit area because it is a dimensionless quantity. Stress, strain and Young’s modulus has the dimensions of force per unit area and their SI unit is Nm-2.
10. What are the dimensions of strain?
a) No dimensions
b) Nm
c) Nm-2
d) Nm-1
View Answer
Explanation: The definition of strain states that it is a dimensionless quantity because it given the change in dimension over original dimension. Since, the numerator and denominator both have the same dimensions therefore, strain has no dimensions.
Sanfoundry Global Education & Learning Series – Physical Chemistry.
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