1) A…………. is used when large forces act along the screw axis in one direction only:a) Square threadb) Buttress thread c) V thread d) acme thread

2) The efficiency of a square thread screw increases rapidly upto helix angle of:a) 20 b) 45c) 90d) 15

3) Bearing pressure in power screw is:a) w/π.d.tb) w/d.tc) w/ π .d.t.n d) w/π.d^2.t.n

4) The screw is said to be overhauling if efficiency is……………….. 50%:

a) More b) Lessc) Equald) None

5) Screws used for power transmission should have:a) Low efficiencyb) High efficiency c) Very fine threadsd) Strong teeth

1) Which type of springs are mostly used in automobiles:a) Torsion springb) Disc springc) Leaf spring d) Helical spring

2) When the compression spring is compressed until the coil comes in contact with each other then the spring is said to be:

a) Solid length b) Free lengthc) Total length

d) Compressible length3) Which spring is widely used for transmitting small torques as in door hinges ,brush

holder in electric motors:a) Helical torsion spring b) Disc springc) Flat spiral springd) Leaf spring

4) Stress in the full length leaves is……… 50% than the stress in the graduated leaves:a) Greater b) Lessc) Equald) None

5) Deflection of helical springs of circular wire is:a) 8W.C^3.n/G.D^4 b) 8C^3.n/ G.D^4c) 8W.C^3/ G.D^4d) 8W.C^3.n/ D^4e)

1) The…………….are those which can support steady loads without any relative motion b/w journal & bearing:

a) Thin film bearingb) Thick film bearingc) Zero film bearingd) Externally pressurized lubricated bearing

2) It is the ability of bearing material to accommodate small particles of dust ,grit without scoring the material of journal:

a) Bondabilityb) Embeddability c) Comformabilityd) Corrosion resistance

3) The …………. are used with water or other low viscosity lubricants particularly where sand or other large particles are present:

a) Carbon_graphite bearingb) Wood bearingc) Soft rubber bearing d) None of them

4) It is the lowest temperature at which an oil gives off sufficient vapour to support a momentary flash actually setting fire to the oilwhen a flame is brought within 6mm at the surface of oil:

a) Viscosity indexb) Flash point c) Fire point d) Freezing point

5) A ……………. Is used to guide the shaft which is subjected to a load along the axis of the shaft:

a. Thrust bearing b. Footstep bearingc. Collar bearingd. Bushed bearing

1) In helical gears the distance b/w similar faces of adjacent teeth along a helix on the pitch cylinders normal to teeth is called:

a) Normal pitch b) Axial pitchc) Diametral pitchd) Module

2) End thrust given by in helical gears is:a) W tan α b) W cosαc) W sinαd) None

3) The helix angle for double helical gears may be made upto:a) 45 b) 60c) 70d) 90

4) The thickness of rim for the gear is

a) m √Tnb) t√m /nc) m√T /N3

d) m√n/T5) The helix angle for single helical gear ranges from

a) 10____15b) 15____20c) 20____35d) 35____50

1) The bevel gears are used for transmitting power at a………… velocity ratio b/w two shafts whose axis intersect at a certain angle:

a) Uniformb) Variablec) Fluctuatingd) Constant

2) When the teeth on the bevel gear are cut on the inside of the pitch cone then they are known as:

a) Crown bevel gearb) Mitre gear c) Internal bevel gear d) Angular bevel gear

3) The………… angle is equal to the pitch angle plus addendum anglea) Root angleb) Face angle c) Dedendum angled) Helix angle

4) Dedendum cone diameter is given by:a) Dp+2αcosƟpb) D p-2 d cos Ɵp c) Dp+2dcosƟpd) Dp-2αcosƟp

5) For a bevel gear having the pitch angle the ratio of formative no. of teeth to actual no. of teeth:

a) 1/sinƟb) 1/cosƟ c) 1/tanƟd) sinƟ cosƟ

1) The worm gear are widely used for transmitting power at……. Velocity ratios b/w non intersecting shafts that are not generally but not necessary at right angle:

a) Low Velocity

b) High Velocity c) Average Velocityd) Medium Velocity

2) The………… is also used for light service:a) Hobbed straight face worm gear b) straight face worm gearc) Concave face worm geard) Convex face worm gear

3) The………. Angle b/w the tangent to the thread helix on the pitch cylinder and the axis of the worm:

a) Helix angle b) Lead anglec) Tooth pressure angled) Pitch angle

4) The no. of starts on the worm for a velocity ratio of 40 should be: a) Single b) Doublec) Tripled) Quadruple

5) In designing a worm and worm gear which quantity is not given:a) Speedb) Velocityc) Power transmittedd) Lead angle

1-The power screws with multiple threads are usually found in:

a) High speed carsb) High speed toolsc) High speed actuators d) High speed steel

2-The efficiency of square threaded screws may be defined as the ratio between the ideal---------------to the actual effort:

a) Effort b) Loadc) Frictiond) Mechanical advantage

3-Torque required to lower the load i.e T= Wtan(fi-alpha), if fi <alpha then torque will be:

a) Positiveb) Negative c) Bothd) None

4-The co-efficient of friction depends upon various factors like:

a) Material of screwb) Quality of lubricationc) Both d) Only a

5-The slow movement of the screw may be obtained as-------------pitch of threads:

a) Largeb) Mediumc) Small d) Exremely small

6-In a closed coiled helical spring the helix angle is:

a) Greater than 10b) Just equal to 10c) Less than 10 d) Not defined

7-The major stress induced in bellevile spring is:

a) Tensile & shearb) Bending & torsionc) Twist & teard) Tensile & compressive

8-Smaller size wires have:

a) Greater strengthb) Less ductilityc) Less strengthd) ‘a’ & ‘b’

9-In leaf spring the longest leaf is known as:

a) Lower leafb) Upper leaf

c) Both a & bd) Master leaf

10-Spring index ‘C’ is calculated as:

a) d/Db) d/2Dc) D/2dd) D/d

11-In a bush bearing bush can be:

a) Replacedb) Not replacedc) Worn outd) Both a & c

12-The ZN/P factor helps to predict:

a) Performance of springb) Strength of bearingc) Performance of bearing d) None of all

13-The unit of absolute viscosity of the lubricant:

a) Kgm/sb) Nm/sc) Kg/ms d) No units

14-In a thrust bearing the load acts:

a) In any directionb) Along the axis of rotation c) Perpendicular to axis of rotationd) Parallel to axis

15-When the angle of contact of bearing is 120; the bearing is said to be:

a) Partial journal bearing b) Only journal bearingc) Full journal bearingd) Thrust bearing

16-In helical gears, angle ‘fi’ denotes:

a) Helical angleb) Nominal anglec) Normal pressure angle d) a & b

17-The hellix angle for double helical gears may made upto:

a) 90 b) 45c) 75d) 120

18-In helical gears contact between mating teeth is

a) Generalb) Diagonalc) a & bd) gradual

19-If P= 22 kW, speed of the driver in a pair of helical gears is 1800 rpm; the torque transmitted by the pinion will be:

a) 126.7 Nmb) 116.7 Nm c) 100 Nmd) Cannot be calculated

20-The distance of the pitch point from the back of the boss, parallel to the pitch point is called:

a) Cone distanceb) Backing c) Crown heightd) Cone center

21-It is the maximum diameter of the teeth of gear:

a) Mounting heightb) Pitch diameterc) Addendum cone diameter d) Cone center

22-The face angle of a bevel gear is equal to:

a) Pitch angle+Addendum angle b) Pitch angle-Dedendum anglec) Pitch angle+Dedendum angle

d) Pitch angle-Addendum angle

23-It is also linear pitch of a worm:

a) Circular pitchb) Radial pitchc) Diagonal pitchd) Axial pitch

24-Maximum shear stress is calculated by the formula------------------------.

25-In a worm & worm gear worm gear is:

a) Driving memberb) Driven member c) Bothd) None of above

26-Normal pressure angle for triple & quadruple threads for worm gear may be:

a) 6b) 12c) 14.5d) 20

27-In worm gearing the quantity of heat generated is given by the formula------------------------.

28-Conical or volute springs are used in:

a) Telescopy b) Taracopyc) Endotherapyd) Cars

29-The major spring stresses in helical springs are shear stresses due to:

a) Crushingb) Tensionc) Turningd) Twisting

30--------------------spring is used in automobiles of semi-elliptical shape:

a) Conicalb) Coilc) Leaf d) half

1. The material of spring should have

a) High fatigueb) Low resiliencec) High resilienced) Both a and c

2. In closely coiled helical spring the helix angle is very small, it is usually less than

a) 5b) 10 c) 15d) 20

3. Laminated springs is also known as

a) Leaf springsb) Flat springsc) Carriage springsd) All

4. The springs are mostly made from oil tempered carbon steel wires contain carbon

a) 0.4-0.5%b) 0.5-0.6%c) 0.6-0.7% d) 0.7-0.8%

5. The turn which impart spring action are know as

a) Inactive turnb) Active turn c) Effective turnd) None of these

BEARINGS1. The lubricant used to separate the journal and bearing is usually a

a) A mineral oil refined from petroleumb) Vegetable oilc) Silicon oild) All

2. Depending upon the direction of load to be support the bearing under thin group are classified as

a) Radial bearing

b) Thrust bearingc) Both d) None

3. In …… bearing load acts perpendicular to the direction of motion of moving element

a) Radial bearing b) Thrust bearingc) Thick film bearingd) Thin film bearing

4. The …… bearings are these in which the working surfaces are completely separated from each other by the lubricant

a) Thin film bearingb) Thick film bearing c) Zero film bearingd) None

5. The ….. bearing are those which operate without any lubricant present

a) Thick film bearingb) Thin film bearingc) Zero film bearing d) None

WORM GEAR1. Worm gear can give velocity ratio as

a) 100:1b) 200:1c) 300:1 d) 400:1

2. Types of worms

a) Cylindrical wormb) Straight wormc) Cone or double enveloping wormd) All

3. ……is the linear distance through which a point on a thread moves a head in one revolution of worm

a) Axial pitch

b) Lead c) Normal pitchd) None

4. The ……. face worm gear is the accepted standard form and is used for all heavy service

a) Convexb) Roundc) Flatd) Concave

5. The hobbed straight face worm gear is used for …….. services

a) Heavyb) Mediumc) Light

d) All

HELICAL GEAR1. A helical gear has teeth in form of

a) Flatb) Roundc) Helix d) All

2. …… is the distance parallel to axis between similar faces of adjacent teeth

a) Normal pitchb) Pitchc) Axial pitch d) Longitudinal pitch

3. In order to remove axial thrust…………helical gear are used

a) Singleb) Double c) Bothd) None

4. In single helical gear the helix angle ranges from

a) 45-60

b) 30-45c) 20-35 d) 15-30

5. Helical gears are used for

a) Smooth driveb) High efficiency of transmissionc) Both a and b d) Low efficiency of transmission

BEVEL GEARS1. The bevel gears are used for transmitting power at……….between two shafts whose axes

intersect at a certain anglea) Variable velocityb) Constant velocity c) Bothd) None

2. When the bevel gears connect two shafts whose axes intersect at an angle other than a right angle then they are known as

a) Mitre gearb) Angular bevel gear c) Crown bevel geard) Internal bevel gear

3. The bevel gears may have………….teeth

a) Straightb) Flatc) Spirald) Both a and c

4. When the teeth on the bevel gear are cut on inside of pitch cone then they known as

a) Mitre gearb) Angular bevel gearc) Crown bevel geard) Internal bevel gear

5. When bevel gears connect two shafts whose axes intersect at an angle greater than a right angle and one of the bevel gear has a pitch angle of 90 then it is known as a

a) Mitre gearb) Angular bevel gear c) Crown bevel gear d) Internal bevel gear

SCREW

1. The square thread result in maximum efficiency and …… on nut

a) Maximum radial or busting pressureb) Minimum radial or busting pressure c) No radial or busting pressured) None

2. Maximum efficiency of a square threaded screw is

a) 1-sinɸ/1+sinɸ b) 1+sinɸ/1-sinɸc) 1-sinɸ/sinɸ-1d) None

3. The power screws with multiple threads such as double and triple etc are employed when it is desired to secure a……….a) Low efficiencyb) High efficiency c) Both d) None

4. The power screw are used to convert ………motion into………. Motion

a) Linear to rotaryb) Rotary to linearc) Translatory to rotaryd) Rotary to translatory

5. Acme threads are also known as

a) Buttress threadb) Trapezoidal thread c) Square thread

Worm Gear

Types of worm gear are

a) 2 b) 3c) None

……..is mostly as a speed reducers

a) Worm gearingb) Spur gear c) None

If the efficiency of worm gear is less than 50%, then the worm gearing is said to be

a) Self-lockingb) Lockingc) None

The ………. Is used to some extent, but it require extremely accurate alignment

a) Cone or double enveloping worm b) Spur gearc) None

The number of starts on the worm for a velocity ratio of 40 should be

a) Singleb) Doublec) None

Bevel Gear

The……. are used for transmitting power at a constant velocity ratio between two shafts whose axis intersect at a certain angle.

a) Bevel Gearb) Worm Gearc) None

When the teeth on the bevel gear are cut on the inside of pitch cone, they are known as

a) Internal bevel gearb) Bevel gearc) None

The action of …………will be same as that of equivalent spur gear

a) Bevel gearb) Worm gearc) None

The factor(L-B/L) may be called as

a) Bevel factor b) Worm factorc) Both

The face angle of a bevel gear is equal to

a) Pitch angle +addendum angleb) Pitch anglec) None

Helical Gear

…………has teeth in form of hekix around the gear

a) Helical gearb) Worm gearc) None

Helical gears may be of…..

a) Single helical typeb) Double helical typec) Both

……….is a constant angle made by helices with the axis of rotation

a) Helix angleb) Axial p itchc) Both

Mathematically, formative or equivalent number of teeth on a helical gear

a) Te = T/cos3α b) Te = T/sin3αc) None

The helix angle for double helical gears may be made up to

a) 450

b) 700

c) 600

Bearing

A ………… is a machine element which support another moving machine element

a) Bearingb) Gear c) Cam

…….. the load acts perpendicular to the direction of moving element

a) Radial bearingb) Thrust bearingc) Both

When the angle of contact of the bearing with the journal is 3600, then the bearing is called a….

a) Full journal bearing b) Partial journal bearingc) None

……the load acts along the axis of rotation

a) Radial bearing b) Thrust bearingc) None

………..is used for bearing subjected to very high pressure

a) Phosphor bronzeb) Gun mealc) None

Screwed Joints

A …….is formed by cutting a continous helical groove on a cylindrical surface.

a) Screw thread

b) Square threadc) None

………joints are highly reliable in operation

a) Screw jointsb) Riveted jointc) Welded joint

Root diameter or core diameter is

a) Major didameter b) Minor diameterc) None

…….is the surface joining the crest and root

a) Flankb) Rootc) Crest

…….is half the pitch of the thread

a) Slope b) Crest c) Root

Spring

……spring is defined as an elastic body, whose function is to distort when loaded and to recover its original shape when the load is removed.

a) Springb) Shaft c) Cam

The …..may be used only application when the load tends to wind up the spring and are used in various electrical mechanism

a) Torsion springb) Disc spring c) Helical spring

Light service include springs subjected to loads that are……or very infrequently varied in safety valve spring.

a) Static b) Dynamic c) Rolling

…..spring consist of a number of a flat plates.

a) Laminated springb) Leaf springc) Both

The turns which impart spring action are known as…..

a) Active turnsb) Inactive turnsc) Both

Springs

1- Which of the following spring is used in a mechanical wrist watch?(a) Helical compression spring (b) Spiral spring (c) Torsion spring (d) Belleville spring

2- When a helical compression spring is subjected to an axial compressive load, the stress induced in the wire is(a) Tensile stress (b) compressive stress (c) shear stress (d) bending stress

3-The spring mostly used in gramophones is(a) Helical spring (b) conical spring (c) laminated spring (d) flat spiral spring

4- A leaf spring in automobiles is used(a) To apply forces (b) to measure forces (c) to absorb shocks (d) to store strain energy

5- In leaf springs, the longest leaf is known as(a) Lower leaf (b) master leaf (c) upper leaf (d) none of these

Helical Gears

1-Helicalgears may be of or (a) Single helical type (b) double helical type (c) both a & b

2- The helix angle for double helical gears may be made up to(a) 45° (b)60° (c) 75° (d)90°

3- In helical gears, the right hand helices on one gear will mesh ......... helices on the other gear.(a) right hand (b) left hand (c)None

4- In helical gears, the distance between similar faces of adjacent teeth along a helix on the pitch cylinders normal to the teeth, is called(a) Normal pitch (b) axial pitch(c) diametric pitch (d) module

5- The helix angle for single helical gears ranges from(a) 10° to 15° (b) 15° to 20° (c) 20° to 35° (d) 35° to 50°

Bevel Gears

1- If b denotes the face width and L denotes the cone distance, then the bevel factor is written as(a) b / L (b) b / 2L (c) 1 – 2 b.L (d)1 – b / L

2- The face angle of a bevel gear is equal to(a) Pitch angle – addendum angle (b) pitch angle + addendum angle (c) pitch angle –

dedendum angle (d) pitch angle + dedendum angle

3- The root angle of a bevel gear is equal to(a) Pitch angle – addendum angle (b) pitch angle + addendum angle (c) pitch angle –

dedendum angle (d) pitch angle + dedendum angle

4- When bevel gears having equal teeth and equal pitch angles connect two shafts whose axes intersect at right angle, then they are known as(a) Angular bevel gears (b) crown bevel gears (c) internal bevel gears (d) mitre gears

5- For a bevel gear having the pitch angle θ, the ratio of formative number of teeth (TE) to actual number of teeth (T) is(a) 1/sinθ (b) 1/cosθ (c) 1/tanθ (d) sin θ cos θ

Worm Gears

1- The number of starts on the worm for a velocity ratio of 40 should be(a) Single (b) double(c) triple (d) quadruple

2- The axial thrust on the worm (WA) is given by(a) WA = WT .tan φ (b) WA = WT / tan φ(c) WA = WT . tan λ (d) WA = WT / tan λ

3- The worm gears are widely used for transmitting power at ...........velocityratios between non-intersecting shafts.(a)High (b) low

4- In worm gears, the angle between the tangent to the thread helix on the pitch cylinder and the plane normal to the axis of worm is called(a) Pressure angle (b) lead angle (c) helix angle (d) friction angle

5- The normal lead, in a worm having multiple start threads, is given by(a) lN = l / cos λ (b) lN = l . cos λ(c) lN = l (d) lN = l tan

Bearings

1- The ball bearings are usually made from(a) low carbon steel(b) medium carbon steel(c) high speed steel(d) chrome nickel steel

2- The tapered roller bearings can take(a) Radial load only (b) axial load only(c) both radial and axial loads (d) none

3- The piston pin bearings in heavy duty diesel engines are(a) Needle roller bearings (b) tapered roller bearings (c) spherical roller bearings(d)Cylindrical roller bearings

4- Which of the following is antifriction bearing?(a) journal bearing (b) pedestal bearing (c) collar bearing (d) needle bearing

5- Ball and roller bearings in comparison to sliding bearings have(a) More accuracy in alignment (b) small overall dimensions (c) low starting and running friction (d) all of these

Screwed Joints

1- A locking device in which the bottom cylindrical portion is recessed to receive the tip of the locking set screw, is called(a) castle nut (b) jam nut (c) ring nut (d) screw nut

2- Which one is not a positive locking device?(a) Spring washer (b) Cotter pin (c) Tongued washer (d) Spring wire lock

3- The washer is generally specified by its(a) Outer diameter (b) hole diameter (c) thickness (d) mean diameter

4- A locking device extensively used in automobile industry is a(a) jam nut (b) castle nut (c) screw nut (d) ring nut

5-The railway carriage coupling have(a) square threads (b) acme threads (c) knuckle threads (d) buttress threads

Power Screws

1- A screw jack has square threads and the lead angle of the thread is α. The screw jack will be self-locking when the coefficient of friction (µ) is(a) µ > tan α (b) µ = sin α (c) µ = cot α (d) µ = cosec α

2- To ensure self-locking in a screw jack, it is essential that the helix angle is(a) larger than friction angle (b) smaller than friction angle (c) equal to friction angle

(d) such as to give maximum efficiency in lifting

3- A screw is said to be self-locking screw, if its efficiency is (a) less than 50% (b) more than 50% (c) equal to 50% (d) none of these

4- A screw is said to be over hauling screw, if its efficiency is(a) Less than 50% (b) more than 50%(c) equal to 50% (d) none of these5- While designing a screw in a screw jack against buckling failure, the end conditions for the screw are taken as(a) Both ends fixed (b) both ends hinged (c) one end fixed and other end hinged (d) one

end fixed and other end free.

NOTE (answers of the MCQs are underlined )