Mechanical Engineering Quiz # 16

An adiabatic process is one in which

No heat enters or leaves the gas

The temperature of the gas changes

The change in internal energy is equal to the mechanical workdone

All of these

A cycle consisting of one constant pressure, one constant volume and two isentropic processes is known as

Diesel cycle

Stirling cycle

Otto cycle

Carnot cycle

In the first law of thermodynamics, the total energy of the system remains constant.

False

True

The efficiency of Diesel cycle approaches to Otto cycle efficiency when

Cut-off is decreased

Cut-off is constant

Cut-off is increased

Cut-off is zero

The ratio of specific heat at constant pressure (Cp) and specific heat at constant volume (Cv) is

Less than one

None of these

Greater than one

Equal to one

The value of gas constant (R) in S. I. units is

287 J/kgK

28.7 J/kgK

2.87 J/kgK

0.287 J/kgK

The value of specific heat at constant pressure (Cp) is __________ that of at constant volume (Cv).

More than

Less than

Equal to

Water gas is obtained by passing air and a large amount of steam over waste coal at about 650°C.

Incorrect

Correct

Workdone in a free expansion process is

Zero

Maximum

Minimum

Positive

The processes occuring in open system which permit the transfer of mass to and from the system, are known as

Flow processes

None of these

Non-flow processes

Adiabatic processes

The efficiency and work ratio of a simple gas turbine cycle are

High

Very high

Low

Very low

The pressure exerted by an ideal gas is __________ of the kinetic energy of all the molecules contained in a unit volume of gas.

One-third

Three-fourth

Two-third

One-half

The entropy __________ in an irreversible cyclic process.

Decreases

Increases

Remains constant

The distillation carried out in such a way that the liquid with the lowest boiling point is first evaporated and recondensed, then the liquid with the next higher boiling point is then evaporated and recondensed, and so on until all the available liquid fuels are separately recovered in the sequence of their boiling points. Such a process is called

Carbonisation

Fractional distillation

Cracking

Full distillation

There is no change in internal energy in an isothermal process.

Incorrect

Correct

The amount of heat required to raise the temperature of the unit mass of gas through one degree at constant volume, is called

Specific heat at constant pressure

Specific heat at cOnstant volume

None of these

Kilo Joule

The cold chisels are made by

Piercing

Forging

Rolling

Drawing

In a hot chamber die casting machine

Melting pot is separate from the machine

Melting pot is an integral part of the machine

Melting pot may have any location

High temperature and pressure is used

Blanking and piercing operations can be performed simultaneously in a

Combination die

Progressive die

Simple die

Compound die

A saw which cuts wood during the return stroke of the saw is known as

Push saw

Pull saw or draw saw

In a die casting method, the molten metal is forced into mould under high pressure.

Correct

Incorrect

The draft or taper allowance on casting is generally

2 to 5 mm/m

5 to 10 mm/m

10 to 15 mm/m

1 to 2 mm/m

The accuracy of micrometers, calipers, dial indicators can be checked by a

Plug gauge

Slip gauge

Ring gauge

Feeler gauge

Surface plate is used to check the trueness of flat surfaces.

False

True

When a pattern is made in three parts, the bottom part is known as a cope.

True

False

The purpose of a riser is to

Deliver the molten metal from pouring basin to gate

Feed the molten metal to the casting in order to compensate for the shrinkage

Deliver molten metal into the mould cavity

Act as a reservoir for the molten metal

Metal patterns are used for

Small castings

Large scale production of castings

Large castings

Complicated castings

In a centrifugal casting method

Core is made of non-ferrous metal

No core is used

Core is made of sand

Core is made of ferrous metal

The instrument which has all the features of try-square, bevel protractor, rule and scriber, is

Combination set

Inside micrometer

Outside micrometer

Depth gauge micrometer

In __________ welding, the weld may be made either from left to right or from right to left.

Fore-hand

Back-hand

Vertical