Description : Polymers which soften on heating and harden when cooled are (a) Cross-linked polymers (b) Copolymers (c) Thermosetting polymers (d) Thermoplastics
Last Answer : Thermoplastics
Description : Cross linked polymers are (A) Thermoplastic (B) Thermosetting (C) Either (A) or (B) (D) Fibres only
Last Answer : (B) Thermosetting
Description : Interchain forces are the weakest in case of (A) Plastics (B) Fibres (C) Elastomers (D) Both rubber & elastomers
Last Answer : (D) Both rubber & elastomers
Description : Polymers are classified into four categories namely thermosetting, thermoplastic, elastomer and fibre depending upon their (A) Molecular sizes (B) Magnitude of intermolecular forces (C) Resistance to heat (D) Polymerisation mechanism
Last Answer : (B) Magnitude of intermolecular forces
Description : A chain growth polymerisation reaction consists of three different types of reaction namely initiation reaction, propagation reaction & termination reaction. Chain growth polymerisation reaction is not involved ... Siloxane elastomers (B) Polyamides (C) Vinyl polymers (D) Urea-formaldehyde resins
Last Answer : (D) Urea-formaldehyde resins
Description : Elastomers are (A) Thermosetting material (B) Exemplified by protein derivatives (C) Having high flexural strength (D) Having very high tensile strength and heat resistance
Last Answer : (C) Having high flexural strength
Description : Differentiate between any five of the following: a) Thermoplastics and thermosetting plastics b) Lunar eclipse and solar eclipse c) Asteroid and meteorite d) Renewable and non-renewable energy resources e) Endothermic and exothermic reactions f) Star and planet g) Nuclear fission and nuclear fusion
Last Answer : a) Thermoplastics and thermosetting plastics: Thermoplastics: Thermoplastics can be repeatedly softened by heating and hardened by cooling.Thermoplastic molecules, which are linear or slightly branched, do ... or explode in midair. Remains of meteoroids that reach the surface are called meteorites.
Description : Among the following polymers, the strongest molecular forces are present in:
Last Answer : Among the following polymers, the strongest molecular forces are present in: A. elastomers B. fibres C. thermoplastics D. thermosetting polymers
Description : Arrange the following Polymers in increasing order of inter molecular forces Nylon 6, Neoprene and PVC
Last Answer : Ans : Nylon 6, PVC and. Neop
Description : Arrange the following Polymers in increasing order of inter molecular forces. (a) Nylon 66, Buna-S and Polythene (b) Nylon 6, Neoprene and PVC
Last Answer : Ans: (a) Buna-S, Polythene and Nylon 66. (b) Neoprene, PVC and Nylon 6.
Description : Give one example for each of the following types of inter-particle forces (a) London dispersion forces (b)Dipole-Dipole forces (c) Hydrogen bond (d) Ion-dipole forces
Last Answer : Ans. (a) noble gases. (b) between HCl molecules. (c) Between water molecules or HF molecules. (d)Between NO3- and water molecules.
Description : Thermosetting resins/polymers as compared to thermoplastic ones are (A) Soluble in all organic solvents (B) More brittle (C) Formed by addition polymerisation only (D) Easily reshaped & reused
Last Answer : (B) More brittle
Description : Linear polymers are normally (A) Thermosetting (B) Thermoplastic (C) Elastometric (D) Having extremely high softening poin
Last Answer : (B) Thermoplastic
Description : Thermosetting polymers as compared to thermoplastic polymers (A) Are formed by addition polymerisation (B) Have three dimensional structure (C) Have linear structure (D) None of these
Last Answer : (B) Have three dimensional structure
Description : Pick out the wrong statement. (A) Linear polymers are formed from bifunctional groups only and are normally thermoplastic (B) Cross-linked branched chain polymers are either elastometric or ... (D) Dibasic acids reacts with dihydric alcohols to give polyesters using addition polymerisation reaction
Last Answer : D) Dibasic acids reacts with dihydric alcohols to give polyesters using addition polymerisation reaction
Description : Cross linked polymers formed from bi-and trifunctional groups in which cross-linkage in three dimensions via few chemical bonding across linear chains occur imparts to the polymer __________ properties. (A) Thermoplastic (B) Thermosetting (C) Elastometric (D) Brittleness
Last Answer : (C) Elastometric
Description : Thermosetting resins are those polymers, which (A) Do not increase in plasticity with rise in temperature (B) Allow slip to occur between molecules (C) Do not take on a permanent set (D) None of these
Last Answer : (A) Do not increase in plasticity with rise in temperature
Description : Thermosetting polymers are (A) Injection moulded (B) Cast molded (C) Extruded (D) None of these
Last Answer : (B) Cast molded
Description : While the thermosetting polymers are amorphous in nature, the thermoplastic polymers are either amorphous or crystalline. The crystalline polymers are characterised by the (A) Low impact strength (B) High flexibility (C) Better finish and surface appearance (D) High plastic deformation
Last Answer : A) Low impact strength
Description : The inter particle forces between linear chains in nylon-66 are __________ bonds. (A) Hydrogen (B) Covalent (C) Ionic (D) None of these
Last Answer : (A) Hydrogen
Description : List any four properties of thermosetting polymers.
Last Answer : Properties of thermosetting polymers: 1.Very poor elasticity 2.sronger attractive forces between chains 3. not soluble in organic compounds 4.can not be remoulded 5. these polymers produces by condensation polymerization
Description : Differentiate between Thermoplastic and Thermosetting polymers.
Last Answer : Differentiate between Thermosetting and Thermoplastic polymers: Thermosetting Thermoplastic Polymers which once mould /shaped do not soften when heated and thus cannot be reshaped Polymers whose ... tri, tetra or poly functional. Monomer used in this polymer bi functional.
Description : In case of wet spinning of polymers, the polymer solution is forced through spinnerates into, a coagulating bath to give a filament form. Wet spinning is not used in case of the __________ fibres. (A) Viscose rayon (B) Acrylic (C) Polyvinyl acetate (D) Saturated polyeste
Last Answer : (D) Saturated polyeste
Description : Melt spinning of polymers involves the forcing of polymer melt through spinnerates (fine holes) into an atmosphere kept at a temperature lower than the melting point of the polymer, which causes the fine diameter ... the __________ fibres. (A) Acrylic (B) Polyester (C) Nylon 6:6 (D) Polypropylene
Last Answer : (A) Acrylic
Description : Pick out the wrong statement. (A) Polymeric fibres are never produced by addition polymerisation (B) Property of tackiness is exhibited by uncured rubber (C) Sharp melting point is not observed in thermoplastic polymers (D) Polythene generally has an excellent resistance to ultra violet rays
Last Answer : (A) Polymeric fibres are never produced by addition polymerisation
Description : Identify the group in which all the polymers mentioned can be used to make fibres. (A) Butadiene copolymers, Polyamides, Urea-formaldehyde (B) Cellulose derivatives, Polyisoprene, Polyethylene (C) Cellulose derivatives, Polyamides, Polyurethane (D) Polypropylene, Poly vinyl chloride, Silicon
Last Answer : (B) Cellulose derivatives, Polyisoprene, Polyethylene
Description : In case of dry spinning of polymers, the polymer solution in a volatile solvent is forced through the spinnerates into a warm air chamber, where the solvent evaporates leaving behind the polymer in the filament ... is used for __________ fibres. (A) Polythene (B) PVC (C) Rayon (D) Polyvinyl acetate
Last Answer : (B) PVC
Description : Which of the following fibres is considered as the strongest natural fibre? (1) Cotton (2) Jute (3) Wool (4) Silk
Last Answer : Silk
Description : Addition of plasticisers to polymers results in partial neutralisation of intermolecular forces of attraction between the macro-molecules thereby increasing its (A) Tensile strength (B) Chemical resistance (C) Flexibility (D) All (A), (B) & (C)
Last Answer : (C) Flexibility
Description : Out of all the elastomers, natural rubber has the longest elongation range & flexibility of the order of __________ percent. (A) 1-1000 (B) 1000-1500 (C) 1500-2000 (D) 2000-2500
Last Answer : (A) 1-1000
Description : Which of the following is used as base material in Selective laser sintering (SLS)? a.Photopolymer b.Thermoplastics, Metal powders c.Titanium alloys d.Various materials
Last Answer : b.Thermoplastics, Metal powders
Description : Which of the following is used as base material in Stereolithography (SLA) process? a.Thermoplastics , Metals powders b.Thermoplastics , Eutectic metals. c.Titanium alloys d.Photopolymer
Last Answer : d.Photopolymer
Description : Which of the following is not thermoplastics?
Last Answer : Which of the following is not thermoplastics? A. Cellulose acetate B. Nitrocellulose C. Polyvinyl acetate D. Phenol formaldehyde polymer
Description : Classification of polymers on the basis of molecular forces.
Last Answer : (a) Elastomers:- The polymers that have elastic character like rubber are called elastomers. Ex. Natural rubber (b) Fibers:- They have strong intermolecular forces between the chains. These forces ... permanent change on heating. They become hard and infusible on heating. Ex. Bakelite. Etc.
Description : How do Wire Rope Isolators (WRI) compare to elastomers regarding use over a broad temperature range?
Last Answer : The WRI can be used over a greater temperature range with less change in performance. Proper elastomer selection will make elastomers useful for most applications.
Description : What are elastomers ? Give one example.
Last Answer : Ans: The rubber like material which are elastic in nature. Eg. Natural rubber.
Description : Elastomers can extend upto (A) Five times their original dimensions (B) Seven times their original dimensions (C) Ten times their original dimensions (D) Three times their original dimensions
Last Answer : Answer: Option C
Description : Liquid crystal elastomers 4D printing material achieve their activation due to a. Light b. Heat c. Electrical d. All of the above
Last Answer : Ans:- d. All of the above
Description : Elastomers are:** A. Hydrophilic B. Hydrophobic C. Water-loving impression material D. Potassium alginates E. None of the above
Last Answer : B. Hydrophobic
Description : which type of friction forces are the strongest and the weakest?
Last Answer : there are four types of friction: static, sliding, rolling, and air resistance. Static friction is the strongest and rolling friction is weakest.
Description : Where shows the correct order of forces from weakest to strongest?
Last Answer : strong nuclear, weak nuclear, electrostatic, gravitational
Description : In which part of the magnet are magnetic forces strongest?
Last Answer : The magnetic field of a bar magnet is strongest at either pole of the magnet. It is equally strong at the north pole compared with the south pole. The force is weaker in the middle of the magnet and halfway between the pole and the center
Description : How do inter molecular forces affect the boiling point of a liquid?
Last Answer : What is the answer ?
Description : A drop of liquid assumes spherical shape because: (1) Intermolecular forces are strong in liquids (2) A sphere has the least surface area for a given volume (3) A sphere has the largest surface area for a given volume (4) Inter molecular forces are weak in liquids
Last Answer : (2) A sphere has the least surface area for a given volume Explanation: A drop of liquid assumes spherical shape because a sphere has the least surface area for a given volume.
Description : Arrange in increasing order of inter molecular forces. Nylon 66, Buna-S and polyethene.
Last Answer : Ans: Nylon 66 > polyethene> Buna-S
Description : Honey contain glucose and fructose along with some other ingredients, it has greater viscosity due to------? A. hydrogen bonding B. irregular shape of the molecules C. irregular shape of the molecules and strong inter-molecular forces (Answer) D. greater molecular size
Last Answer : C. irregular shape of the molecules and strong inter-molecular forces (Answer)
Last Answer : A sphere has the least surface area for a given volume
Description : __________ forces act on a particle moving through a stationary fluid (A) Gravity (B) Drag (C) Buoyant (D) All (A), (B), & (C)
Last Answer : (D) All (A), (B), & (C)
Description : A spherical particle is falling slow in a viscous liquid such that Reynolds number is less than 1. Which statement is correct for this situation? (A) Inertial and drag forces are important (B) Drag ... forces are important (C) Drag force and gravitational forces are important (D) None of the above
Last Answer : (B) Drag, gravitational and buoyancy forces are important
Description : Forces acting on a particle settling in fluid are __________ forces. (A) Gravitational & buoyant (B) Centrifugal & drag (C) Gravitational or centrifugal buoyant drag (D) External, drag & viscous
Last Answer : (C) Gravitational or centrifugal buoyant drag