Description : The best lubricants for a machine working at high temperature & load is (A) Grease (B) Solid lubricant (C) Animal oils (D) Mineral oils
Last Answer : Option B
Description : When replacing a power transistor fitted with a heat sink in a circuit, a coating of silicone grease is applied between the transistor case and the heat sink. This is done to ____________. A. lubricate ... the heat sink C. aid in the removal of the heat sink D. provide maximum heat transfer
Last Answer : Answer: D
Description : .The most resistant filling materials to fill class IV cavities are: A. Resins with silicone dioxide (SiO2) B. Resins with glass or quartz C. Silico-phosphate D. Silicates
Last Answer : B. Resins with glass or quartz
Description : Rank the following impressions materials according to their flexibility A. Alginate> Polysulphide> Silicone> Zinc Oxide Eugenol B. Silicone> Alginate> Polysulphide> Zinc Oxide Eugenol C. ... Eugenol> Silicone> Polysulphide 300.Denture resins are usually available as powder and liquid that
Last Answer : D. Alginate> Silicone> Polysulfide> Zinc Oxide Eugenol
Description : _______is suitable as a lubricant for heavy-duty applications of rolling contact bearing. (a) Grease (b) Lubricating oil (c) Graphite (d) Air
Last Answer : (b) Lubricating oil
Description : ________is suitable as a lubricant for low and moderate loads applications of rolling contact bearing. (a) Grease (b) Lubricating oil (c) Graphite (d) Air
Last Answer : (a) Grease
Description : In hydrostatic bearings (A) The Oil film pressure is generated only by the rotation of the journal (B) The oil film is maintained by supplying oil under pressure (C) Do not require external supply of lubricant (D) Grease is used for lubrication
Last Answer : (B) The oil film is maintained by supplying oil under pressure
Description : Thermoplastic resins are those polymers, which (A) Has decreased plasticity at increasing temperature (B) Cannot be moulded (C) Easily deform under pressure at high temperature (D) None of these
Last Answer : (C) Easily deform under pressure at high temperature
Description : Amino resins are used in paper treatment to improve its (A) Wet tear and bursting strength (B) Folding endurance (C) Wet rub resistance (D) All (A), (B) & (C)
Last Answer : (D) All (A), (B) & (C)
Description : Ebonite is a/an (A) Highly vulcanised rubber (B) Natural rubber (C) Unvulcanised raw rubber (D) Adhesive
Last Answer : (A) Highly vulcanised rubber
Description : Thermoplastic resins usually (A) Remain hard as long as they are hot (B) Cannot be reclaimed from waste (C) Permanent setting resins (D) Less brittle than thermosetting resins
Last Answer : (D) Less brittle than thermosetting resins
Description : The effect of the temperature rising above 100ºC on heat-cured denture-base acrylic resins is: A. Produces porosity on the external portion of the resin. B. Produces porosity on the internal portion ... porosity on the surface of the resin. D. Prevents porosity on the interior of the resin
Last Answer : B. Produces porosity on the internal portion of the resin.
Description : Polyurethane cannot be used to make (A) Automobile cushion (B) Thermal insulation in refrigerator (C) Coating and adhesive (D) Fibre reinforced plastic (FRP)
Last Answer : (D) Fibre reinforced plastic (FRP)
Description : Epoxy resin (A) Is a good adhesive (B) Is an elastomer (C) Cannot be used for surface coatings (D) Is a polyester
Last Answer : (A) Is a good adhesive
Description : In step growth polymerisation, generally only one type of reaction & some basic mechanism is involved. Step growth polymerisation reaction is not involved in the manufacture of (A) Cross linked polystyrene (B) Phenol formaldehyde resins (C) Polyesters (D) Polyamides
Last Answer : (A) Cross linked polystyrene
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 : 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 : Size reduction of moulding powders, waxes, resins & gums are done in a __________ mill. (A) Cage (B) Hammer (C) Both (A) & (B) (D) Neither (A) nor (B)
Last Answer : (C) Both (A) & (B)
Description : Fibre reinforced plastic (FRP) are (A) Made of glass fibre and thermoplastic resins (B) Anisotropic (C) Made of thermosetting resin and glass fibre (D) Both 'b' & 'c'
Last Answer : Option D
Description : Rosin soap is added during paper manufacture to (A) Impart adhesive properties (B) Improve opacity (C) Impart resistance to penetration by liquids (D) None of these
Last Answer : (C) Impart resistance to penetration by liquids
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 : Self polymerising acrylic resins differ from heat cured resins because they exhibit: A. Higher molecules weight B. Higher content of residual monomers
Last Answer : B. Higher content of residual monomers
Description : Water drops cannot stick to the oily surface due to – (1) lack of adhesive force (2) surface tension (3) cannot mix each other (4) water is lighter than oil
Last Answer : (2) surface tension Explanation: The separation of oil and water is caused due to the difference in surface tension of the two liquids. The water molecules stick together tightly and does not mix ... to each other very strongly, forming an invisible "skin" of surface tension around each drop.
Description : Water drops cannot stick to the oily surface due to (1) lack of adhesive force (2) surface tension (3) cannot mix each other (4) water is lighter than oil
Last Answer : surface tension
Description : Zinc is highly __________ at room temperature. (A) Ductile (B) Resistant to atmospheric corrosion (C) Malleable (D) Brittle
Last Answer : (B) Resistant to atmospheric corrosion
Description : Ammonium nitrate (is mixed with limestone) is not used as fertiliser as such, because (A) It is hygroscopic and explosive in nature (B) It is highly acidic in nature (C) It is a liquid at room temperature (D) Its nitrogen content is very less
Last Answer : (A) It is hygroscopic and explosive in nature
Description : Why can the fluids used to dry clean clothing remove in grease even when water cannot?
Last Answer : Feel Free to Answer
Description : Mineral oils (e.g. petroleum oils) are preferred over fatty oils (e.g. mustard oil, ghee, tallow, palm oil, olive oil etc.) as a lubricant due to its (A) Poor oxidation stability and high gum forming ... at elevated temperature (C) Hydrolysis tendency in presence of water (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : Assertion (A): In anti-friction bearings, the frictional resistance is very low as the shaft held by it remains in floating condition by the hydrodynamic pressure developed by the lubricant. [IES-2006] Reason (R): In hydrodynamic ... of A (c) A is true but R is false (d) A is false but R is true
Last Answer : (d) A is false but R is true
Description : Consider the following statements: [IES 2007] For a journal rotating in a bearing under film lubrication conditions, the frictional resistance is- 1. Proportional to the area of contact 2. Proportional to the viscosity of lubricant 3. ... 4 (b) 1 and 4 only (c) 2, 3 and 4 only (d) 2 and 3 only
Last Answer : (a) 1, 2, 3 and 4
Description : Which of the following statements regarding evacuated tube collectors (ETC) are true? i) ETC is used for high temperatures upto 150oC ii) because of use of vacuum between two concentric glass tube, higher amount of heat is ... upon the ambient temperature i & iii b) ii & iii c) i & iv d) i & ii
Last Answer : d) i & ii
Description : Babbitt metal used for making bearings should have (A) High co-efficient of friction between journal and bearing (B) Ability to retain lubricant on its surface (C) Low co-efficient of friction between journal and bearing (D) Both (B) & (C)
Last Answer : (A) High co-efficient of friction between journal and bearing
Description : Viscosity index improver (like polystyrene or polyisobutylene) is added to lubricant to (A) Reduce its viscosity (B) Increase its viscosity (C) Reduce the variation in its viscosity with temperature (D) Increase the variation in its viscosity with temperature
Last Answer : (C) Reduce the variation in its viscosity with temperature
Description : Grease coatings on electrical contact surfaces increase contact resistance and should be removed with a/an _______________. A. small wire brush B. compressed air jet C. clean dry cloth D. 10% solution carbon solvent and water
Last Answer : Answer: C
Last Answer : 10 ohm
Description : Wrought iron is (A) High carbon iron (B) Highly resistance to acid corrosion (C) Malleable & ductile; and hence is used for chain links, hooks & couplings (D) An alloy of iron, chromium & carbon
Last Answer : (C) Malleable & ductile; and hence is used for chain links, hooks & couplings
Description : In the desorption of highly soluble gas from the liquid, the main resistance will be in the __________ phase. (A) Gas (B) Liquid (C) Both (A) & (B) (D) Neither (A) nor (B)
Last Answer : (B) Liquid
Description : Tubeless tyres are made of __________ rubber, which is a co-polymer of isoprene & isobutylene. (A) Nitrile (B) Silicone (C) Neoprene (D) Buty
Last Answer : (D) Buty
Description : Epoxy resin is a polymer containing two or more groups of the bellow fig. is called epoxide group or ethoxyline group. It is a (A) Polyamide & an elastomer (B) Good adhesive (C) Surface coating agent (D) Both (B) and (C)
Last Answer : (D) Both (B) and (C)
Description : Which of the following materials may prove unsuitable for handling acetic acid (glacial & anhydrous) at 40°C? (A) Silicone rubber, teflon, porcelain and wood (B) Nickel, monel, stainless steel and graphite (C) Aluminium, copper, high silicon iron (D) Brass, cast iron, mild steel and tin
Last Answer : (D) Brass, cast iron, mild steel and tin
Description : H2SO4 (< 50% concentration) is corrosive to (A) Aluminium, mild steel, stainless steel, concrete & tin (B) Copper, cast iron & high silicon iron (14% Si) (C) Rubber (butyl and hard), silicone rubber & Teflon (D) Glass, graphite, porcelain & stoneware
Last Answer : (A) Aluminium, mild steel, stainless steel, concrete & tin
Description : Pick out the wrong statement. (A) Surface tension of a liquid is because of the difference in magnitude of adhesive & cohesive forces (B) A hydrometer used for the determination of ... Turbulent fluid flow is characterised by the rapid fluctuation of instantaneous pressure & velocity at a poin
Last Answer : (C) In case of unsteady fluid flow, the velocity at any given point does not change with time
Description : If an alternator is to be inactive for a considerable period of time, which of the following actions should be taken? A. It should be disconnected from the prime mover and raised off its bearing supports ... . D. The windings and collector rings should be protected with a thin coat of grease or oil.
Description : Which of the following rubbers has the widest service temperature range (-75 to 275°C)? (A) Butyl rubber (B) Silicon rubber (C) Nitrile rubber (D) Silicone rubber
Last Answer : (D) Silicone rubber
Description : Preheating before welding is done to (A) Make the plate softer (B) Burn oil & grease sticking to plate surfaces (C) Avoid plate distortion (D) Prevent cold cracks
Last Answer : (D) Prevent cold cracks
Description : Penetration test determines the __________ of the grease. (A) Stiffness (B) Lubricating properties (e.g. oilness) (C) Service temperature (D) Variation in viscosity with temperature
Last Answer : (A) Stiffness
Description : Would a water repellent spray make a jacket reasonably usable in a light rain?
Last Answer : It depends on the jacket. Some clothes etc. are designed to be waterproof but only are if you spray the seams, for example. Other clothes etc. are not designed to be waterproof, and spraying them won't ... spray documentation, or good sales staff (e.g. at REI) to figure out what works best on what.
Description : Metalloids (A) Are good conductor of heat & electricity (B) Act as electron donors with metals & as electron acceptor with non metals (C) Are not necessarily solids at room temperature ... & non-metallic properties to some extent and are exemplified by elements like germanium, silicon & boron
Last Answer : D) Are compounds that exhibit both metallic & non-metallic properties to some extent and are exemplified by elements like germanium, silicon & boron
Description : Which of the following parameters is not responsible for the heat loss from a hot steam carrying bare pipe surface located in a room without fans? (A) Emissivity of pipe surface (B) Diameter & length of the pipe (C) Temperature of hot pipe surface & that of air in the room (D) None of thes
Description : Can heat effect the adhesive on Velcro dots?
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