Mechanical Engineering Quiz # 13

The correct sequence of tool materials in increasing order of their ability to retain their hot hardness is

Carbide, ceramic, cermet, borazon

Cermet, carbide, ceramic, borazon

Borazon, ceramic, carbide, cermet

Ceramic, carbide, borazon, cermet

The method of grinding used to produce a straight or tapered surface on a workpiece, is

External cylindrical grinding

Form grinding

Internal cylindrical grinding

Surface grinding

In orthogonal cutting system, the maximum chip thickness occurs at the middle.

Incorrect

Correct

Twist drills are made of

Carbon steel

Stainless steel

High speed steel

Either high speed steel or carbon steel

The different spindle speeds on a lathe form

Any one of these

Harmonical progression

Arithmetical progression

Geometrical progression

Drilling is an example of

Simple cutting

Uniform cutting

Orthogonal cutting

Oblique cutting

Which of the following statement is correct for a compound steam engine?

The temperature range per cylinder is increased, with corresponding increase in condensation.

The cost of the engine, for the same power and economy, is more than that of a simple steam engine.

The forces in the working parts are increased as the forces are distributed over more parts.

The ratio of expansion is reduced, thus reducing the length of stroke.

A device used to increase the temperature of saturated steam without raising its pressure, is called

Superheater

Fusible plug

Stop valve

Blow off cock

The object of producing draught in a boiler is

To provide an adequate supply of air for the fuel combustion

All of these

To discharge the gases of combustion to the atmosphere through the chimney

To exhaust the gases of combustion from the combustion chamber

The rate of steam produced in Benson boiler is

175 tonnes/h

250 tonnes/h

135 tonnes/h

100 tonnes/h

In a glass tube type water indicator for a boiler, one end of the tube is connected to water space and the other end is connected to

Water space also

Superheater

Steam space

Chimney

Fire tube boilers are

Externally fired

None of these

Internally as well as externally fired

Internally fired

Which of the following boiler is best suited to meet the fluctuating demand of steam?

Cornish boiler

Lancashire boiler

Locomotive boiler

Babcock and Wilcox boiler

The fire tubes in a Cochran boiler are

Vertical

Inclined

Horizontal

A safety valve mainly used with locomotive and marine boilers is

High steam and low water safety valve

Spring loaded safety valve

Dead weight safety valve

Lever safety valve

La-mont boiler, is a high pressure water tube steam boiler working on forced circulation.

Agree

Disagree

The diameter of flue tube in a Cornish boiler is __________ that of the shell.

One-fourth

One-third

Two-fifth

Three-fifth

Which of the following statement is wrong?

Water tube boilers are internally fired.

Locomotive boiler is a water tube boiler.

La-mont boiler is a low pressure water tube boiler.

All of these

An economiser __________ the steam raising capacity of a boiler.

Increases

Has no effect on

Decreases

Which of the following statement is correct?

All of these

Fire tube boilers are internally fired.

Babcock and Wilcox boiler is a water tube boiler.

Lancashire boiler is a fire tube boiler.

In water tube boilers

None of these

Water passes through the tubes which are surrounded by flames and hot gases

The flames and hot gases pass through the tubes which are surrounded by water

Forced circulation takes place

Pick Up the following statement is correct?

A fire tube boiler occupies less space than a water tube boiler, for a given power.

A simple vertical boiler has one fire tube.

All of these

Steam at a high pressure and in large quantities can be produced with a simple vertical boiler.

An air preheater is installed

None of these

Before the superheater

Before the economiser

Between the economiser and chimney

Select the following statement is wrong?

The factor of evaporation for all boilers is always greater than unity.

The amount of water evaporated in kg per kg of fuel burnt is called equivalent evaporation from and at 100° C.

None of these

The ratio of heat actually used in producing the steam to the heat liberated in the furnace is called boiler efficiency.

The power of a boiler may be defined as

The amount of water evaporated or steam produced in kg per kg of fuel burnt

The amount of water evaporated from and at 100° C into dry and saturated steam

The evaporation of 15.653 kg of water per hour from and at 100° C

The ratio of heat actually used in producing the steam to the heat liberated in the furnace

In a reciprocating steam engine, the heat energy in the steam is converted into mechanical work by the to and fro motion of the piston.

Disagree

Agree

De-Laval turbine is a

None of these

Simple impulse turbine

Simple reaction turbine

Impulse-reaction turbine

The critical pressure ratio for initially dry saturated steam is more as compared to initially wet steam.

No

Yes

Rateau turbine is

Pressure compounded turbine

Simple reaction turbine

Pressure-velocity compounded turbine

Velocity compounded turbine

The rate of discharge through the nozzle __________ when the exit pressure is gradually reduced.

Remains same

Increases

Decreases