Electrical Power Engineering Multiple Choice Questions and Answers (MCQs) Part 10:
452. ………. is a process that is generally used in winter air-conditioning.
(a) Humidification
(b) Dehumidification
(c) Heating and humidification
(d) Heating and dehumidification
Answer : (c) Heating and humidification
453. Air is dehumidified by
(a) cooling.
(b) chemical absorption.
(c) heating.
(d) both (a) and (b).
Answer : (d) both (a) and (b).
454. Compared to individual systems, the central air-conditioning system has ……….. overall efficiency.
(a) higher
(b) lower
(c) same
(d) unpredictable
Answer : (a) higher
455. The main disadvantage(s) of central type air-conditioning s/are that
(a) dusting is very costly.
(b) absence of any individual room temperature adjustments.
(c) cigarette smoke and bacteria present in the return air from infected rooms redistribute to healthy rooms.
(d) all of the above.
Answer : (c) cigarette smoke and bacteria present in the return air from infected rooms redistribute to healthy rooms.
456. Which of the following unitary-central systems are in common use?
(a) Fan coil units.
(b) Induction units.
(c) All air high velocity systems.
(d) All of the above.
Answer : (d) All of the above.
457. The conditions conductive to comfort depends upon ………..
(a) humidity
(b) temperature
(c) air movement
(d) air purity
(e) all of the above factors
Answer : (e) all of the above factors
458. Main traction systems used in India are those using ………. locomotives.
(a) steam engine
(b) diesel engine
(c) diesel-electric
(d) electric
(e) all of the above
Answer : (e) all of the above
459. The steam engine provided on steam locomotive is
(a) double acting condensing type.
(b) double acting non-condensing type.
(c) single acting condensing type.
(d) single acting non-condensing type.
Answer : (b) double acting non-condensing type.
460. In case of steam locomotives the tractive effort is provided by
(a) double cylinder, double acting steam engine.
(b) double cylinder, single acting steam engine.
(c) single cylinder, double acting steam engine.
(d) single cylinder, single acting steam engine.
Answer : (a) double cylinder, double acting steam engine.
461. In case of a steam locomotive an average coal consumption per km of run is around
(a) 5-10 kg
(b) 25-30 kg
(c) 60-80 kg
(d) 100-150 kg
Answer : (b) 25-30 kg
462. The pressure of steam used in steam locomotives is about
(a) 1-5 kgf/cm2
(b) 5-10 kgf/cm2
(c) 10-15 kgf/cm2
(d) 20-30 kgf/cm2
Answer : (c) 10-15 kgf/cm2
463. The maximum horse power of steam locomotive is
(a) up to 1,500
(b) 1,500-2,000
(c) 2,000-3,000
(d) 3,000-4,000
Answer : (a) up to 1,500
464. The speed of a steam locomotive is controlled by
(a) applying brakes.
(b) gearbox.
(c) regulating steam flow to engine.
(d) flywheel.
Answer : (c) regulating steam flow to engine.
465. The pulsating torque exerted by steam locomotives causes
(a) jolting and skidding.
(b) hammer blow.
(c) pitching.
(d) all of the above.
(e) jolting and skidding.
Answer : (a) jolting and skidding.
466. Steam engine drive
(a) has limited overload capacity.
(b) is not clean drive.
(c) is not suitable for urban or suburban services or for hauling heavy loads on steep gradients.
(d) all of the above.
Answer : (d) all of the above.
467. Steam locomotives
(a) cannot be put into service at any moment.
(b) cause considerable wear on the track.
(c) need more repair and maintenance.
(d) all of the above.
Answer : (d) all of the above.
468. Steam engine drive is not suitable for urban and suburban services as
(a) it is not clean drive.
(b) coefficient of adhesion of steam locomotives is quite low.
(c) steam locomotive causes considerable wear on the track.
(d) steam locomotive has limited speed.
Answer : (b) coefficient of adhesion of steam locomotives is quite low.
469. Direct internal combustion drive
(a) has higher maintenance and operating costs.
(b) has no starting torque and needs some auxiliary means for its starting.
(c) has shorter life of propulsive equipment.
(d) all of the above.
Answer : (d) all of the above.
470. Diesel electric traction has comparatively limited overload capacity because
(a) diesel engine is a constant output prime mover.
(b) diesel engine has shorter life span.
(c) regenerative braking cannot be employed.
(d) diesel-electric locomotive is heavier than an ordinary electric locomotive.
Answer : (a) diesel engine is a constant output prime mover.
471. The range of horse power of diesel locomotives is
(a) 100-500
(b) 1,500-2,500
(c) 3,000-4,500
(d) 4,500-5,000
Answer : (b) 1,500-2,500
472. In India, diesel locomotives are manufactured at
(a) Varanasi.
(b) Kolkata.
(c) Bangalore.
(d) Ajmer.
Answer : (a) Varanasi.
473. In diesel-electric drive
(a) initial investment required is low.
(b) locomotive and train is a self-contained unit.
(c) power loss in speed control is low.
(d) all of the above.
Answer : (d) all of the above.
474. Battery driven vehicles
(a) are easy to control and very convenient to use.
(b) have low maintenance cost.
(c) cause no pollution.
(d) all of the above.
Answer : (d) all of the above.
475. Battery operated trucks are used
(a) in power stations.
(b) for local delivery of goods in large towns with maximum daily run up to 50-60 km.
(c) in narrow gauge traction.
(d) for main line service.
Answer : (b) for local delivery of goods in large towns with maximum daily run up to 50-60 km.
476. Electric traction in comparison to other traction systems has the advantage(s) of
(a) higher acceleration and braking retardation.
(b) cleanest system and so ideally suitable for the underground and tube railways.
(c) better speed control.
(d) all of the above.
Answer : (d) all of the above.
477. Electric railway can handle the traffic upto double the amount possible with steam railway. It is because of
(a) better speed control.
(b) larger passenger carrying capacity.
(c) higher schedule speed.
(d) both (b) and (c).
Answer : (d) both (b) and (c).
478. Electric traction in comparison to other traction systems has the drawback(s) of
(a) interference with communication lines running along the track.
(b) heavy initial expenditure in laying out overhead electric supÂply system.
(c) interruption of traffic for hours owing to short time power failure.
(d) all of the above.
Answer : (d) all of the above.
479. The most vital factor against electric traction is
(a) its high maintenance cost.
(b) possibility of power failure.
(c) high initial cost in laying out overhead electric supply system.
(d) necessity of providing a negative booster.
Answer : (c) high initial cost in laying out overhead electric supply system.
480. The locomotive that has the highest operational availability is
(a) diesel-electric.
(b) electric.
(c) steam.
(d) steam-electric.
Answer : (b) electric.
481. Unbalanced forces are maximum in case of
(a) diesel shunters.
(b) diesel locomotives.
(c) steam locomotives.
(d) electric locomotives.
Answer : (c) steam locomotives.
482. Maintenance requirements are minimum in case of
(a) electric locomotives.
(b) steam locomotives.
(c) diesel electric locomotives.
(d) diesel engines.
Answer : (a) electric locomotives.
483. A drive suitable for mines where explosive gas may exist, is
(a) steam engine.
(b) battery locomotive.
(c) diesel engine.
(d) any of the above.
Answer : (b) battery locomotive.
484. A submarine is provided driving power through (while moving under water)
(a) diesel engines.
(b) steam engines.
(c) batteries.
(d) gas turbine.
Answer : (c) batteries.
485. Ordinary tramway is the most economical means of transport for
(a) very dense traffic in large cities.
(b) rural services.
(c) suburban services.
Answer : (a) very dense traffic in large cities.
486. Unlike a tramway, a trolley bus needs no
(a) driving axles.
(b) running rail.
(c) hand brakes.
(d) overhead contact wire.
Answer : (b) running rail.
487. The direct current system employed for tramways operates on
(a) 3,000 V
(b) 1,500 V
(c) 750 V
(d) 400 V
Answer : (c) 750 V
488. For tramways the return circuit is
(a) track rails.
(b) neutral wire.
(c) common earthing.
(d) cables.
Answer : (a) track rails.
489. For 600 V dc line for tramcars, track is connected to the
(a) positive of the supply.
(b) negative of the supply.
(c) midvoltage of 300 V.
(d) none of the above.
Answer : (b) negative of the supply.
490. In tramways
(a) the power is supplied at 600 V dc from a single overhead conductor of + ve polarity.
(b) the speed is controlled by field weakening or series-parallel control.
(c) rheostatic and mechanical brakings are employed for normal service.
(d) all of the above.
Answer : (d) all of the above.
491. The main drawback of tramways is that
(a) the life of tramcar equipment is short.
(b) it has restricted manoeuvrability.
(c) it needs laying overhead supply system and track for its use, which is costly to maintain and constitutes a source of danger to other road users.
(d) all of the above.
Answer : (c) it needs laying overhead supply system and track for its use, which is costly to maintain and constitutes a source of danger to other road users.
492. The trolley bus
(a) is an electrically operated pneumatic tyred vehicle, usually fed at 600 V dc from two overhead contact wires.
(b) is able to manoeuvre in a traffic over a width of several metres on either side of the central line of the trolley wires.
(c) uses field weakening method for its speed control.
(d) all of the above.
Answer : (d) all of the above.
493. The trolley buses
(a) do not require laying of track for its use as return conductor.
(b) make use of foot operated master controllers.
(c) make use of stabilized rheostatic braking.
(d) all of the above.
Answer : (d) all of the above.
494. In diesel electric traction
(a) the driving motors are dc series type and fed from the dc generators driven by the diesel engine put on the same locoÂmotive.
(b) the starting and speed control is affected by varying the exciÂtation of the generator.
(c) regenerative braking is not possible.
(d) all of the above.
Answer : (d) all of the above.
495. Suburban railways use
(a) 1,500 V dc.
(b) 400 V, 3-phase ac.
(c) 3,300 V, 3-phase ac.
(d) 600 V, 3-phase ac.
Answer : (a) 1,500 V dc.
496. Long distance railways operate on
(a) 600 V dc.
(b) 25 kV single-phase ac.
(c) 25 kV three-phase ac.
(d) 15 kV three-phase ac.
Answer : (b) 25 kV single-phase ac.
497. The electric locomotives run faster at curved routes in comparison to steam locomotives because
(a) its centre of gravity is lower than that of steam locomotive.
(b) its centre of gravity is higher than that of steam locomotive.
(c) the speed at curved routes is independent of locations of centre of gravity.
(d) none of the above.
Answer : (a) its centre of gravity is lower than that of steam locomotive.
498. Low frequency operation of overhead line in traction system
(a) increases the spacing between substations.
(b) reduces the spacing between substations.
(c) spacing is independent of frequency of supply.
Answer : (a) increases the spacing between substations.
499. In Kando system of track electrification
(a) single-phase ac is converted into dc.
(b) single-phase ac is converted into 3-phase ac.
(c) 3-phase ac is converted into dc.
(d) 3-phase ac is converted into single-phase ac.
Answer : (b) single-phase ac is converted into 3-phase ac.
500. The composite system (single-phase ac to dc system) has been chosen for all future track electrification in India as
(a) it needs light overhead catenary.
(b) it needs less number of substations.
(c) it combines the advantages of high-voltage ac distribution at 50 Hz with dc series traction motors.
(d) it provides flexibility in the location of substations.
Answer : (c) it combines the advantages of high-voltage ac distribution at 50 Hz with dc series traction motors.
501. Single-phase ac system is preferred for main line railway service because
(a) the initial, maintenance and operating costs of ac substations are less as the substation equipment required in single-phase ac system is less, cheap and efficient.
(b) number of substations required is less.
(c) of reduced cost of distribution system.
(d) all of the above.
Answer : (d) all of the above.