Mechanical Engineering Quiz # 12

Circumferential joint in boilers is used to get the required length of a boiler.

False

True

A screw is said to be over hauling screw, if its efficiency is

None of these

Equal to 50%

Less than 50%

More than 50%

In a hydrodynamic lubricated bearing

There is a thin film of lubricant between the journal and the bearing

There is no lubricant between the journal and the bearing

There is a thick film of lubricant between the journal and the bearing

The lubricant is forced between the journal and the bearing, by external pressure

A transmission shaft includes

Line shaft

Over head shaft

All of these

Counter shaft

Which of the following statement is correct for gears?

The addendum is less than dedendum

The pitch circle is always greater than the base circle

All of these

The pitch circle diameter is equal to the product of module and number of teeth

Lewis equation in gears is used to find the

Shear stress

Fatigue stress

Compressive stress in bending

Tensile stress in bending

A crankshaft is a __________ shaft.

Transmission

Machine

The resistance to fatigue of a material is measured by

Endurance limit

Ultimate tensile strength

Elastic limit

Young's modulus

In order to avoid tearing of the plate at an edge, the distance from the centre line of the rivet hole to the nearest edge of the plate should be equal to (where d = Diameter of rivet hole)

2 d

D

2.5 d

1.5 D

The property of a material which enables it to be drawn into wires with the application of a tensile force, is called

Ductility

Malleability

Elasticity

Plasticity

An open belt drive is used when

Shafts are arranged parallel and rotate in the same directions

Shafts are arranged parallel and rotate in the opposite directions

Driven shaft is to be started or stopped whenever desired without interferring with the driving shaft

Shafts are arranged at right angles and rotate in one definite direction

The value of stress concentration factor depends upon

None of these

Material of the part

Geometry of the part

Material and geometry of the part

Screws used for power transmission should have

Low efficiency

Strong teeth

High efficiency

Very fine threads

The cam follower extensively used in air-craft engines is

Flat faced follower

Roller follower

Spherical faced follower

Knife edge follower

When bevel gears connect two shafts whose axes intersect at an angle greater than a right angle and one of the bevel gears has a pitch angle of 90°, then they are known as

Internal bevel gears

Mitre gears

Crown bevel gears

Angular bevel gears

The number of rivets in shear shall be equal to the number of rivets in crushing.

Incorrect

Correct

A fixture is defined as a device which

Is used to check the accuracy of workpiece

All of these

Holds and locates a workpiece and guides and controls one or more cutting tools

Holds and locates a workpiece during an inspection or for a manufacturing operation

The example of snag grinding is

Trimming the surface left by sprues and risers on castings

Grinding the parting line left on castings

All of these

Removing flash on forgings

The cutting tool in a milling machine is mounted on

Knee

Column

Arbor

Spindle

If the diameter of the hole is subject to considerable variation, then for locating in jigs and fixtures, the pressure type of locator used is

Conical locator

Diamond pin locator

Vee locator

Cylindrical locator

When the cutting edge of the tool is dull, then during machining

No chips are formed

Continuous chips are formed

Discontinuous chips are formed

Continuous chips with built-up edge are formed

The average cutting speed for turning brass with a high speed steel tool is

90 to 120 m/min

60 to 90 m/min

15 to 19 m/min

25 to 31 m/min

Cemented carbide tool tips are produced by powder metallurgy.

False

True

A single point thread cutting tool should ideally have

Point angle

Negative rake angle

Positive rake angle

Zero rake angle

Which of the following statement is wrong about ultra-sonic machining?

It is best suited for machining hard and brittle materials.

It produces good surface finish.

It cuts materials at very slow speeds.

It removes large amount of material.

The rake angle required to machine brass by high speed steel tool is

-10°

0°

10°

20°

Segmental chips are formed during machining

Cast iron

Mild steel

High carbon steel

High speed steel

Cast iron during machining produces

Continuous chips with built-up-edge

None of these

Continuous chips

Discontinuous chips

A drill considered as a cutting tool having zero rake, is known as a

Flat drill

Parallel shank twist drill

Tapered shank twist drill

Straight fluted drill

In order to prevent tool from rubbing the work __________ on tools are provided.

Rake angles

Relief angles