chemical engineering Mcqs
251. Resistance of an electrical conductor is proportional to its (where, l = length and A = crosssectional area of the conductor)________________?
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A. A

B. l

C. A2

D. Both A. & B.
252. The substance used as a smoke screen in warfare is___________________?
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A. P2O5

B. C2H2

C. PCl5

D. SiCl4
253. Difference at any instant between the value of the controlled variable and the set point is called the__________________?
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A. Deviation

B. Error ratio

C. Differential gap

D. Derivative time

254. What is the value of included angle of a triangular notch for maximum discharge ?
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A. 90

B. 120

C. 60

D. 30

255. X-rays are__________________?
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A. Positively charged

B. Neutral

C. Of higher wavelength than visible light

D. Negatively charged

256. In condensers used in thermal power plants, steam is normally used in shell side and cooling water on the tube side, because of the reason that ?
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A. Compared to the mass flow rate of cooling water, the rate of condensation of steam is

B. ause of its lower specific volume compared to steam

C. Maintaining vacuum on tube side is more difficult than that on the shell side

D. ariably smaller

E. Water velocity can be increased conveniently to increase the overall heat transfer co-efficient

F. Condenser can act as a storage unit for condensed steam

257. Evaporative cooling process employs a combination of cooling and humidification in which the____________________?
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A. Sensible heat is removed and the latent heat is added

B. Sensible heat is added and latent heat is removed

C. Sensible heat is added

D. Latent heat is removed

258. Moist air is cooled along the line of constant ________________ , when it is passed over a cold & dry cooling coil, such that no condensation occurs ?
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A. Relative humidity

B. Dew point temperature

C. Enthalpy

D. Wet bulb temperature

259. Brittleness induced due to the presence of sulphur in steel can be reduced by adding______________?
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A. Manganese

B. Vanadium

C. Magnesium

D. Copper

260. For a thermodynamic system undergoing a process, which of the following pairs best expresses the relationship similar to that expressed by the pressure volume plot ?
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A. Enthalpy entropy

B. Enthalpy-pressure

C. Temperature pressure

D. Temperature entropy
261. Thermodynamic cycle involved in the working of a thermal power plant is the ______________ cycle ?
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A. Carnot

B. Brayton

C. Joule

D. Rankine
262. Which of the following metals is the most prone to work hardening ?
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A. Lead

B. Brass

C. Aluminium

D. Copper

263. Increasing sulphur content in pig iron tends to make it ________________?
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A. Ductile & malleable

B. Tough

C. Soft

D. Hard
264. Midrex process of sponge iron production uses reformed natural gas as the reducing agent, which uses iron ore in the form of_________________?
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A. Pellets

B. Briquettes

C. Sinter

D. Lumps

265. At 100% relative humidity, the dew point temperature of moist air is_________________?
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A. Equal to the wet bulb temperature

B. Equal to the ambient temperature

C. More than the wet bulb temperature

D. Less than the wet bulb temperature

266. Steel containing low percentage of nickel, chromium & tungsten are termed as the _____________ steel ?
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A. Tool

B. Wrought

C. Plain carbon

D. Alloy

267. Wohler test is a destructive test to find out the ___________________ strength of a prepared metal specimen ?
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A. Endurance

B. Tensile

C. Fatigue

D. Creep

268. Chromium molybdenum steel cannot be welded using ______________ welding ?
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A. Oxy-acetylene

B. Thermit

C. Any of these

D. Electrical resistance
269. A high pressure boiler generates steam at a pressure greater than _____________________ kg/cm2 ?
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A. 80

B. 30

C. 50

D. 10

270. Square steel key is normally strong in failure by shear & crushing. Keys are normally made of _______________ steel bars?
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A. Forged

B. Cold rolled mild

C. Hot rolled mild

D. Machinable stainless

271. The phenomenon occurring during explosion of a hydrogen bomb is___________________?
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A. Nuclear fission

B. Nuclear fusion

C. A combination of both nuclear fission & fusion

D. None of these

272. For preparation of porous bearings by powder metallurgy, preferred particle shape is___________________?
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A. Irregular

B. No preferred shape

C. Nodular

D. Spherical
273. Which of the following is preferred for riveting ?
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A. Butt joint

B. Lap joint

C. Neither A. nor B.

D. Either A. or B.

274. Gage pressure within a spherical droplet of a fluid is p. What will be gage pressure within a bubble of the same size & of the same fluid ?
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A. 2 p

B. p

C. 0.25 p

D. 0.5 p

275. Fatigue resistance of a material is measured by the _____________________?
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A. Elastic limit

B. Youngs modulus

C. Ultimate tensile strength

D. Endurance limit
276. Change in volume of metals from absolute zero temperature to their melting points is___________________?
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A. Almost same for all metals

B. Less for low melting point metals

C. Different for different metals

D. Less for high melting point metals

277. Heat transfer to the water wall in a high pressure water wall type boiler furnace is mainly by_________________?
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A. Conduction

B. Convection

C. Radiation

D. Both A. & B.

278. Which of the following is an undesirable property of slag produced during the Pyrometallurgical method of metal extraction from its ore ?
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A. Low density

B. High fusibility & fluidity

C. High chemical activity

D. High thermal conductivity
279. Heating the Hypo-eutectoid steels to 30C above the upper critical temperature line, soaking at that temperature and then cooling slowly to the room temperature to form a pearlite & ferrite structure is called_______________________?
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A. Normalising

B. Hardening

C. Annealing

D. Tempering

280. Larger length & diameter water pipes are made by____________________?
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A. Electrical resistance welding

B. Continuous casting

C. Die casting

D. Semi-centrifugal casting
281. Annealing of white cast iron produces _____________________ iron?
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A. Grey

B. Malleable

C. Spheroidal

D. Nodular

282. Out of the following, which will fracture most readity, when hit with a hard hammer ?
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A. Cast iron

B. Brass

C. German silver

D. Bronze

283. _______________ is the trade name assigned to a non-ferrous cast alloy composed of cobalt, chromium & tungsten ?
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A. Alnico

B. Stellite

C. High speed steel

D. Cermet

284. Sudden fall of atmospheric pressure by a large amount is an indication of the_____________________?
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A. Rain

B. Cold wave

C. Fair weather

D. Storm
285. Baffles provided on the shell side of a shell and tube heat exchanger are meant for _____________________?
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A. Providing support for the tubes

B. Improving heat transfer

C. Both A & B

D. Preventing the fouling of tubes & stagnation of shell side fluid

286. The Al2O3 content of cryolite in Hall-Heroult cell is maintained between _______________ percent ?
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A. 12-Jun

B. 18-20

C. 15-Dec

D. 2-5
287. The hardenability of steel decreases with__________________?
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A. Decrease in grain size

B. Increase in solutionising temperature

C. Increase in strength

D. Decrease in dislocation density

288. Wavelength of radiation emitted by a body depends on the ________________ of its surface?
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A. Nature

B. Area

C. All A, B & C

D. Temperature
289. Dielectric___________________?
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A. Need not defy the corrosive action of chemicals

B. Of low resistivity is preferred

C. Is an electrical insulating material

D. Should have high thermal conductivity

290. In a neutral solution__________________?
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A. H+ ions are absent

B. OH- ions are absent

C. Both H+ and OH- ions are present in very small but equal concentration

D. None of these

291. Dephosphorization of molten pig iron is favoured by_______________________?
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A. Oxidising and basic slag

B. Oxidising and neutral slag

C. High activity co-efficient of phosphorous in metal

D. Reducing and basic slag
292. The dimensional formula of bulk modulus of elasticity is same as that of the ____________________?
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A. None of these

B. Pressure

C. Force

D. Density

293. Elimination of brittleness resulting from welding of saw blades is done by __________________ of the welded portion ?
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A. Tempering

B. Annealing

C. Work hardening

D. Toughening

294. Out of the following, the ________________ pipe has the least corrosion resistance?
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A. Copper

B. Mild steel

C. Cast iron

D. Wrought iron
295. Lead is poured into the joints between two ___________________ pipes?
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A. Steel

B. Cast iron

C. Concrete

D. Plastic

296. The yield point phenomenon observed in annealed low carbon steel is due to the presence of the following element ?
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A. Carbon

B. Silicon

C. Chromium

D. Phosphorous

297. Ice point is designated on Fahrenheit temperature scale by__________________?
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A. 0

B. 32

C. 212

D. 62

298. A cylindrical rod subjected to a tensile strain within the elastic limit undergoes a volume change. If the volume strain is equal to half the tensile strain, then the Poissons ratio of the rod is___________________?
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A. 0.44

B. 0.33

C. 0

D. 0.25

299. Circular cross section machine parts which are symmetrical about the axis of rotation are made by hot_____________________?
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A. Spinning

B. Drawing

C. Piercing

D. Extrusion

300. The starting of a car takes time in winter, because the__________________?
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A. Octane number of fuel is decreased

B. Vaporisation of the fuel is decreased

C. Pour point of fuel decreases

D. Fuel supply for ignition is not sufficient