Mechanical Engineering Quiz 17

1 / 50

Volumetric efficiency of a compressor with clearance volume ________________?

decreases with increase in compression ratio

increases with increase in compression ratio

may increase/decrease depending on compressor capacity

in not dependent upon compression ratio

2 / 50

The time of completing a project in network analysis is given by following time of the critical activity meeting at the finalitiode_________________?

late start

late finish

early finish

early start

3 / 50

Solder is an alloy consisting of________________?

tin and copper

lead and zinc

tin and lead

tin, antimony, copper

4 / 50

For the same diameter and thickness of tube, a water tube boiler compared to a fire tube boiler has ____________________?

less heating surface

equal heating surface

heating surface depends on other parameters

more heating surface

5 / 50

Octane number is determined by comparing the performance of the petrol with the following hydrocarbons__________________?

mixture of methane and ethane

alpha methyl napthalene

iso-octane

mixture of normal heptane and iso-oc-tane

6 / 50

Hardness of upper bainite (acicular structure) is about___________________?

RC 80

RC 48

RC 57

RC 65

7 / 50

Brass contains___________________?

70-75% copper and rest tin

70% copper and 30% zinc

90% copper and 10% tin

85-92% copper and rest tin with little lead and nickel

8 / 50

As the turbine inlet temperature increases, the thermal efficiency of gas turbine for the optimum pressure ratio_____________________?

remains same

decreases

increases

first increases and then decreases

9 / 50

The efficiency of jet engine is__________________?

higher at high altitudes

same at all altitudes

higher at ground

higher at high speed

10 / 50

Boiling water reactor employs__________________?

direct cycle of coolant system

multi pass system

boiler

double circuit system of coolant cycle

11 / 50

In a Carnot cycle, heat is transferred at_______________________?

constant volume

constant pressure

constant temperature

constant enthaply

12 / 50

Thermal conductivity of air at room temperature in kcal/m hr ?C is of the order of__________________?

0.01

0.02

0.1

0.002

13 / 50

If rain is falling in the opposite direction of the movement of a pedestrain, he has to hold his umbrella ________________________?

less inclined when standing

less inclined when moving

more inclined when moving

more inclined when standing

14 / 50

Medium specific speea of turbine implies it is___________________?

impulse turbine

Francis turbine

propeller turbine

any one of the above

15 / 50

In nuclear fission___________________?

the original elements change into completely different elements

the molecules rearrange themselves to form other molecules

none of the above

the electrons of the element change

16 / 50

Split nut is a locking device in which_________________?

a hard fiber or nylon cotter is recessed in the nut and becomes threaded as the nut is screwed on the bolt causing a tight grip

through slots are made at top and a cotter-pin is passed through these and a hole in the bolt, and cotter pin splitted and bent in reverse direction at the other end

a slot is cut partly in middle of nut and then slot reduced by tightening screw

one smaller nut is tightened over main nut and main nut tightened against smaller one by loosening, creating friction jamming

17 / 50

The energy required to be applied to a radioactive nucleus for the emission of a neutron is________________?

7.8 MeV

1 MeV

4.3 MeV

2.4 MeV

18 / 50

?Killed steels? are those steels__________________?

which are deoxidised in the ladle with silicon and aluminium

which are destroyed by burning

which after their destruction are recycled to produce fresh steel

in which carbon is completely burnt

19 / 50

Two non-collinear parallel equal forces acting in opposite direction__________________?

balance each other

constitute a moment of couple

constitute a moment

constitute a couple

20 / 50

In reaction turbine, draft tube is used_____________________?

to convert the kinetic energy to flow energy by a gradual expansion of the flow cross-section

for safety of turbine

to transport water downstream without eddies

to increase flow rate

21 / 50

One of the purposes of sub-cooling the liquid refrigerant is to________________?

ensure that only liquid and not the vapour enters the expansion (throttling) valve

reduce compressor discharge temperature

increase cooling effect

reduce compressor overheating

22 / 50

A file removes the metal during___________________?

forward stroke

both forward and return strokes

none of these

return stroke

23 / 50

Volatility of diesel fuel oil is_________________?

indicated by 90% distillation temperature, i.e., when 90% of sample oil has distilled off

it catches fire without external aid

temperature at which it solidifies or congeals

minimum temperature to which oil is heated in order to give off inflammable vapours in sufficient quantity to ignite momentarily when brought in contact with a flame

24 / 50

Ratio of indicated h.p. to shaft h.p. in known as__________________?

volumetric efficiency

compressor efficiency

isothermal efficiency

mechanical efficiency

25 / 50

Overfire burning is the phenomenon of _____________________?

supply of excess, air

fuel bed firing

burning CO and unburnts in upper zone of furnace by supplying more air

supply of excess coal

26 / 50

The unit of Young?s modulus is__________________?

kg/cm

mm/mm

kg/cm2

27 / 50

The index of compression n tends to reach ratio of specific heats y when____________________?

process is isothermal

process is isentropic

flow is uniform and steady

process is isentropic and specific heat does not change with temperature

28 / 50

If the evaporator temperature of a plant is lowered, keeping the condenser temperature constant, the h.p. of compressor required will be________________?

more/less depending on rating

less

same

29 / 50

Where does the lowest temperature occur in a vapour compression cycle ?

condenser

evaporator

compressor

expansion valve

30 / 50

The resultant of all normal pressures acts___________________?

vertically upwards

at center of pressure

at metacentre

at e.g. of body

31 / 50

Bar charts are suitable for_____________________?

minor works

all of the above

major works

large projects

32 / 50

An optimum project schedule implies_______________?

to produce best results under given constraints

timely execution of project

optimum utilization of men, machines and materials

lowest possible cost and shortest possible time for project

33 / 50

Which of the following is the binding material in cemented carbides___________________?

iron

vanadium

nickel

cobalt

34 / 50

Job enrichment technique is applied to_________________?

overcome boring and demotivating work

reduce labour monotony

make people happy

all of the above

35 / 50

Solid injection in I.C engines refers to injection of________________?

liquid fuel and air

solid fuel

liquid fuel only

solid fuel and air

36 / 50

The endurance limit in shear of carbon steel can be obtained by multiplying the endurance limit in flexure by a factor of____________?

0.45

0.55

0.75

0.25

37 / 50

In its simplest form, a cam mechanism consists of following number of links___________________?

38 / 50

Increase in pressure at the outer edge of a drum of radius R due to rotation at corad/sec, full of liquid of density p will be___________________?

pco2/?2/2

2pa2R2

pco2/?2

pa2R/2

39 / 50

The number of drums in Benson steam generator is_________________?

no drum

one

two

one steam drum and one water drum

40 / 50

Gear box is used___________________?

to produce torque

to obtain variable speeds

for speed reduction

to increase efficiency of system

41 / 50

Manometer is used to measure__________________?

pressure in pipes, channels etc

very low pressure

atmospheric pressure

difference of pressure between two points

42 / 50

PERT has following time estimate_________________?

three time estimate

one time estimate

two time estimate

four time estimate

43 / 50

Fire tube boilers are those in which__________________?

tubes are laid vertically

forced circulation takes place

flue gases pass through tubes and water around it

water passes through the tubes and flue gases around it

44 / 50

Joule sec is the unit of_________________?

thermal conductivity

universal gas constant

kinematic viscosity

Planck?s constant

45 / 50

Which is correct statement ?

both will be equally rigid

a member made of cast iron will generally be. more rigid than a member of equal load carrying ability made of steel

which one is rigid will depend on several other factors

a member made of steel will generally be more rigid than a member of equal load-carrying ability made of cast iron

46 / 50

A sudden fall in the barometer reading is a sign of approaching________________?

rains

fine weather

storm

cold wave

47 / 50

Which of the following particles is the lightest__________________?

proton

meson

nucleus

electron

48 / 50

Preheating is essential in welding ___________________?

high speed steel

all of the above

cast iron

all non-ferrous materials

49 / 50

The surface hardness of the following order is achieved by nitriding operation__________________?

1000 to 1100 VPN

1500 VPN

600 VPN

250 VPN

50 / 50

A stoichiometric air-fuel ratio is______________________?

rich mixture for idling

chemically correct mixture

rich mixture for over loads

lean mixture

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