1. The relative instability of any of the intermediate skew conformations is due to ___________
a) Lateral strain
b) Shear strain
c) Longitudinal strain
d) Torsional strain
Explanation: The relative instability of any of the intermediate skew conformations is due to torsional strain. Torsion energy can be used to solve problems of general relativity especially the singularity problem.
2. In gauche conformations, the methyl groups are ___________
a) 600 apart
b) 900 apart
c) 1800 apart
d) 3600 apart
Explanation: In gauche conformations, the methyl groups are 600 apart. In general a gauche rotamer is less stable than an anti-rotamer.
3. Both anti and gauche conformations are free of torsional strain.
a) True
b) False
Explanation: Both anti and gauche conformations are free of torsional strain. In general, a gauche rotamer is less stable than an anti-rotamer.
4. Gauche conformation is less stable due to _______________
a) Hydrogen bonding
b) Covalent bonding
c) Vander Waal’s repulsion
d) Torsional strain
Explanation: Gauche conformation is less stable due to Vander Waal’s repulsion. Vander Waal’s are weak forces of attraction which results in lesser stability of gauche conformer.
5. Which of the following is least stable?
a) Anti conformation
b) Gauche conformation
c) Staggered conformation
d) Eclipsed conformation
Explanation: Eclipsed conformation is the least stable due to its high torsional energy. The potential energy of n-butane is maximum for eclipsed conformations.
6. Potential energy remains same during the rotation about the carbon-carbon of n-butane.
a) True
b) False
Explanation: Potential energy changes during the rotation about the carbon-carbon of n-butane. The potential energy of n-butane is maximum for eclipsed conformations and minimum for staggered conformations.
7. Based on the important category, concrete and fibre glass are the examples of ___________
a) Ceramics
b) Polymers
c) Composites
d) Semi-conductors
Explanation: Example of ceramic are Al2O3 and ZrO2, Polymers are Thermoplastic and Thermosets, Composites are Fibre glass and Concrete and Semi-conductors are Silicon and Germanium.
8. Which of the following is not an inorganic functional material?
a) Ferroelectric
b) Reverse micelles
c) Magnetic field sensor
d) Light detectors
Explanation: Reverse micelles is an organic functional material.
9. Which of the following is not an aerospace material?
a) Plastics
b) Silica
c) Aluminium alloys
d) Polymers
Explanation: Polymers are not categorized under aerospace materials.
10. Select the incorrect statement from the following option.
a) Metals are extremely good conductors of heat and electricity
b) The properties of metal degrade rapidly with temperature
c) Metals have poor corrosion resistant
d) A polished metal surface has a dull appearance
Explanation: A polished metal surface has a lustrous appearance. All the other options are correct. Metals are extremely good conductors of heat and electricity, its properties degrade rapidly with temperature and have poor corrosion resistance.