Electrical Power Engineering Multiple Choice Questions and Answers (MCQs) Part 9:
402. Desired illumination level on the working plane depends upon
(a) age group of observers.
(b) whether the object is stationary or moving.
(c) size of the object to be seen and its distance from the obÂserver.
(d) all of the above.
Answer : (d) all of the above.
403. Which of the following will need the highest level of illumination ?
(a) Living room.
(b) Kitchen.
(c) Proof reading.
(d) Hospital wards.
Answer : (c) Proof reading.
404. Which of the following will need the lowest level of illumination ?
(a) Workshop.
(b) Displays.
(c) Railway platform.
(d) Garage.
Answer : (c) Railway platform.
405. The illumination level in houses is in the range of
(a) 20-50 lux.
(b) 100-200 lux.
(c) 300-500 lux.
(d) 700 lux.
Answer : (b) 100-200 lux.
406. The illumination level required for precision work is about
(a) 500-1,000 lux.
(b) 250 lux.
(c) 100 lux.
(d) 50 lux.
Answer : (a) 500-1,000 lux.
407. The illumination level required for important traffic routes carryÂing fast traffic is about
(a) 30 lux.
(b) 100 lux.
(c) 200 lux.
(d) 5 lux.
Answer : (a) 30 lux.
408. Illumination due to moon light is about
(a) 0.03 lumen/m2.
(b) 0.3 lumen/m2.
(c) 30-50 lumens/m2.
(d) 300-500 lumens/m2.
Answer : (b) 0.3 lumen/m2.
409. The luminous flux reaching the working plane least depends on
(a) proportion of the room.
(b) the lumen output of the lamps.
(c) colour of the working plane surface.
(d) reflectance of internal surfaces.
Answer : (c) colour of the working plane surface.
410. The depreciation factor depends upon
(a) ageing of the lamp(s).
(b) lamp cleaning schedule.
(c) type of work carried out at the premises.
(d) all of the above.
Answer : (d) all of the above.
411. Utilization factor depends upon
(a) size of the room.
(b) space-height ratio of the lamps.
(c) colour of walls/ceiling.
(d) all of the above.
Answer : (d) all of the above.
412. Glare is reduced by
(a) increasing the mounting height of the lamp.
(b) using diffusers.
(c) using reflectors to cut-off the light at certain angle.
(d) all of the above.
Answer : (d) all of the above.
413. The glass that transmits the maximum light is
(a) clear glass.
(b) milk glass.
(c) serrated glass.
(d) opalescent glass.
Answer : (a) clear glass.
414. The glass that transmits the least amount of light is
(a) clear glass.
(b) milk glass.
(c) serrated glass.
(d) opalescent glass.
Answer : (b) milk glass.
415. The surface that has the lowest reflection factor for white light is
(a) white oil paint.
(b) white plaster work.
(c) blue curtains.
(d) aluminium sheet.
Answer : (c) blue curtains.
416. The lamp is provided with a reflector in order to
(a) avoid glare.
(b) provide better illumination.
(c) protect the lamp.
(d) all of the above.
Answer : (d) all of the above.
417. Reflectors are provided with slits at the top so as to
(a) reduce heating effect.
(b) reduce colour effect.
(c) introduce chimney effect for cleaning.
(d) all of the above.
Answer : (d) all of the above.
418. Heat from light source is particularly of importance in
(a) designing for air-conditioning.
(b) designing for illumination level.
(c) designing for floor space utilization.
(d) all of the above.
Answer : (a) designing for air-conditioning.
419. Dimming systems for lights are used in
(a) auditoriums.
(b) theatres.
(c) ball room.
(d) all of the above.
Answer : (d) all of the above.
420.The voltage required to pass the necessary current through an electrolytic cell is of the order of
(a) 1-2 V
(b) 10-20 V
(c) 100-120 V
(d) 150-200 V
Answer : (a) 1-2 V
421. The energy consumption for production of ammonium sulphate is of the order of
(a) 2,000-2,500 kWh/tonne.
(b) 3,000-4,000 kWh/tonne.
(c) 4,000-7,000 kWh/tonne.
(d) 70-80 kWh/tonne.
Answer : (a) 2,000-2,500 kWh/tonne.
422. Materials used for copper plating are
(a) copper sulphate and sulphuric acid.
(b) copper sulphate and nitric acid.
(c) copper carbonate and ammonium carbonate.
(d) copper nitrate and sulphuric acid.
Answer : (a) copper sulphate and sulphuric acid.
423. Materials used for chromium plating are
(a) chromium carbonate and sulphuric acid.
(b) chromic acid and sulphuric acid.
(c) chromium chloride and hydrochloride acid.
(d) none of the above.
Answer : (b) chromic acid and sulphuric acid.
424. The gold plating is carried out
(a) with a current density of 150-250 A/m2 at a voltage of 1-2 V.
(b) with a current density of 50-150 A/m2 at a voltage of 5-15 volts.
(c) with a current density of 100-150 A/m2 at a voltage of 1-4 volts.
(d) with a current density of 50-150 A/m2 at a voltage of 1 volt.
Answer : (b) with a current density of 50-150 A/m2 at a voltage of 5-15 volts.
425. Power supply required for electrolytic processes is
(a) alternating current (100-200 A) at very low voltage (10 or 12 V).
(b) direct current (100-200 A) at very high voltage.
(c) direct current (100-200 A) at very low voltage (10 or 12 V).
(d) alternating current at very high voltage.
Answer : (c) direct current (100-200 A) at very low voltage (10 or 12 V).
426. The plants for extraction and refining of metals or large scale manufacturing are located near the
(a) atomic power station.
(b) hydroelectric power station.
(c) steam power station.
(d) either atomic power station or hydroelectric power station.
Answer : (d) either atomic power station or hydroelectric power station.
427. The process of coating of a metallic surface with a harder metal by electrodeposition is called
(a) electro facing.
(b) electroforming.
(c) electro metallisation.
(d) either (a) or (b).
Answer : (a) electro facing.
428. Basically electroplating means
(a) formation of ions by two metallic plates in the acidic liquid.
(b) electrodeposition of metal on electrodes.
(c) electrodeposition of metal upon metallic surfaces.
(d) none of the above.
Answer : (c) electrodeposition of metal upon metallic surfaces.
429. Electroplating is done for
(a) replacement of worn out material.
(b) protection of metals against corrosion.
(c) giving a shining appearance to articles.
(d) all of the above.
Answer : (d) all of the above.
430. The preparation of an object for electroplating involves the
(a) removal of oil, grease or other organic material.
(b) removal of rust, scale, oxides, or other inorganic coatings adhering to the metal.
(c) mechanical preparation of the metal surface by polishing, buffing etc.
(d) any or all of the above operations.
Answer : (d) any or all of the above operations.
431. A one tonne refrigerating machine means that
(a) the total weight of the machine is one tonne.
(b) the quantity of the refrigerant used is one tonne.
(c) one tonne of water can be converted into ice.
(d) one tonne of ice when melts from and at 0°C in 24 hours, the refrigerating effect is equivalent to 14,000 kJ per hour.
Answer : (d) one tonne of ice when melts from and at 0°C in 24 hours, the refrigerating effect is equivalent to 14,000 kJ per hour.
432. The capacity of a refrigerating machine is expressed as
(a) inside volume of the cabinet.
(b) lowest temperature attained.
(c) gross weight of machine in tonnes.
(d) rate of abstraction of heat from the space being cooled.
Answer : (d) rate of abstraction of heat from the space being cooled.
433. Which of the following properties of a refrigerant is undesirable ?
(a) High critical temperature.
(b) Low specific heat of liquid.
(c) High boiling point.
(d) Low specific volume of vapour.
(e) High latent heat of vapourisation.
Answer : (c) High boiling point.
434. Various desirable properties which should be possessed by refrigerants are
(a) non-corrosive and non-inflammability.
(b) no-toxic and freedom from objectionable odour with low working pressure.
(c) both (a) and (b).
(d) none of the above.
Answer : (c) both (a) and (b).
435. In a refrigeration cycle, the flow of refrigerant is controlled by
(a) compressor.
(b) expansion valve.
(c) condenser.
(d) evaporator.
Answer : (b) expansion valve.
436. Which part of the vapour compression refrigeration cycle, produces the refrigeration effect ?
(a) Evaporator.
(b) Condenser.
(c) Expansion valve.
(d) Compressor.
Answer : (a) Evaporator.
437. ………… is used as refrigerant in a vapour absorption refrigerator.
(a) Acqua ammonia
(b) Freon
(c) Water
(d) Sulphur dioxide
Answer : (a) Acqua ammonia
438. The refrigerant Freon 12 is a compound consisting of
(a) carbon, fluorine and chlorine.
(b) carbon, chlorine and hydrogen.
(c) carbon, fluorine and hydrogen.
(d) chlorine, bromine and iodine.
Answer : (a) carbon, fluorine and chlorine.
439. Ammonia is preferred as a refrigerant in large commercial installations because
(a) it is non-tonic.
(b) it has a low working pressure.
(c) it is relatively cheap.
(d) it has low latent heat.
Answer : (b) it has a low working pressure.
440. In a vapour compression system, which of the following units is adversely affected by the presence of moisture ?
(a) Evaporator.
(b) Expansion valve.
(c) Compressor.
(d) Condenser.
Answer : (b) Expansion valve.
441. In a vapour absorption system lithium bromide is used as
(a) refrigerant.
(b) lubricant.
(c) absorbent.
(d) cooling substance.
Answer : (c) absorbent.
442. Vapour absorption refrigeration systems have the advantage(s) of
(a) absence of moving parts.
(b) universal power source.
(c) automatic defrostration.
(d) both (a) and (b).
Answer : (d) both (a) and (b).
443. Thermoelectric refrigeration system has the advantage(s) of
(a) small initial cost.
(b) absence of moving parts.
(c) ease of automatic control by variation of magnitude of current.
(d) both (b) and (c).
Answer : (d) both (b) and (c).
444. In a domestic refrigerator, compressor and motor are assembled in a single unit known as ……… sealed unit.
(a) hermetically
(b) homogeneously
(c) heterogeneously
(d) none of these
Answer : (a) hermetically
445. Hermetically sealed units have the advantage(s) of
(a) relatively silent operation.
(b) minimum gas leakage problem because no moving part extends through the sealing housing.
(c) minimum maintenance requirement.
(d) all of the above.
Answer : (d) all of the above.
446. Which of the following motors is used in household refrigerators ?
(a) DC shunt motor.
(b) Reluctance motor.
(c) Single phase induction motor.
(d) Synchronous motor.
Answer : (c) Single phase induction motor.
447. The compressor of a domestic refrigerator has been noted to run for comparatively large durations, it indicates that
(a) thermostat has become defective.
(b) the machine is overloaded.
(c) capillary tube is choked.
(d) none of the above.
Answer : (b) the machine is overloaded.
448. In a refrigerator, defrosting may be done by
(a) opening the door of the refrigerator.
(b) stopping the compressor for a while.
(c) placing trays of warm waters in the refrigerator.
(d) any of the above.
Answer : (d) any of the above.
449. Types of water coolers are
(a) instantaneous or pressure type.
(b) storage type.
(c) exhaust fan type.
(d) both (a) and (b).
Answer : (d) both (a) and (b).
450. Air-conditioning is the simultaneous control of ………… in a confined space.
(a) temperature
(b) humidity
(c) air movement
(d) temperature, humidity, purity and movement of air
Answer : (d) temperature, humidity, purity and movement of air
451. ………….. is a process which is generally used for summer air-conditioning.
(a) Cooling with dehumidification
(b) Chemical dehumidification
(c) Adiabatic cooling
(d) Cooling with humidification
Answer : (a) Cooling with dehumidification