I85PREP
⌘ K
Tamil Nadu HSE First Year Basic Mechanical Engineering study materials
Tamil Nadu HSE First Year Basic Mechanical Engineering study resources

Tamil Nadu HSE First Year Basic Mechanical Engineering practice questions

One question at a time. Build your Tamil Nadu HSE First Year Basic Mechanical Engineering understanding.

First 50 of 200 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Engineering Materials

In a tensile test, the property measured by the straight-line portion of the stress–strain curve up to the limit of proportionality is called

  1. malleability
  2. elasticity
  3. toughness
  4. stiffness Correct answer.

Explanation

Within the limit of proportionality, stress is directly proportional to strain, so the slope of the straight-line part of the stress–strain diagram gives Young's modulus, which expresses stiffness. Elasticity only means recovery of shape on unloading, and toughness relates to energy absorbed up to fracture.

Question 2Engineering Materials

A specimen of steel has an original gauge length of 50 mm and shows a total elongation of 10 mm at fracture. Its percentage elongation is

  1. 25%
  2. 10%
  3. 5%
  4. 20% Correct answer.

Explanation

Percentage elongation is the increase in gauge length at fracture divided by the original gauge length, multiplied by 100. Here 10/50 × 100 gives 20 per cent, which is a standard measure of ductility.

Question 3Engineering Materials

The property of a material that enables it to be drawn into thin wires is

  1. sonorosity
  2. hardness
  3. ductility Correct answer.
  4. brittleness

Explanation

Ductility is the property that allows a material to undergo permanent deformation in tension, so it can be drawn into wires, as in copper and mild steel. Brittleness is the opposite tendency to fracture with little deformation.

Question 4Engineering Materials

Which of the following is a ferrous engineering material?

  1. Gunmetal
  2. Copper
  3. Aluminium
  4. Cast iron Correct answer.

Explanation

Ferrous materials are those whose principal constituent is iron, and cast iron is an iron–carbon alloy with carbon above about 2 per cent. Copper, aluminium and gunmetal contain no iron as the base element.

Question 5Engineering Materials

In the designation of a plain carbon steel such as 45C8, the number 45 indicates the

  1. percentage of manganese in the steel
  2. ultimate tensile strength in N/mm²
  3. average percentage of carbon multiplied by 100 Correct answer.
  4. Brinell hardness number

Explanation

In the Indian standard designation of plain carbon steels, the first number gives the average carbon content in hundredths of a per cent, so 45C8 means about 0.45 per cent carbon with a manganese range coded by 8. Hardness and strength are not written into this part of the code.

Question 6Engineering Materials

The main reason for adding silicon to cast iron is to

  1. prevent formation of graphite
  2. reduce fluidity of the molten metal
  3. increase the sulphur content
  4. promote graphitisation and improve casting characteristics Correct answer.

Explanation

Silicon is a strong graphitiser in cast iron; it promotes the precipitation of carbon as graphite, which improves machinability and casting behaviour and reduces chill. It also raises the silicon content needed for a sound grey iron structure.

Question 7Engineering Materials

Which heat treatment is applied to relieve internal stresses developed in a weldment without significantly changing its microstructure?

  1. Case carburising
  2. Stress relieving Correct answer.
  3. Annealing to produce coarse pearlite
  4. Hardening

Explanation

Stress relieving heats the component to a temperature below the lower critical temperature, holds it, and cools slowly so that residual stresses relax while the existing microstructure is largely retained. Hardening and carburising deliberately change structure or surface composition.

Question 8Engineering Materials

In the Brinell hardness test, hardness is expressed as the ratio of the applied load to the

  1. curved surface area of the spherical indentation Correct answer.
  2. depth of the indentation
  3. diameter of the ball indenter
  4. diagonal length of the indentation

Explanation

Brinell hardness number is the load divided by the curved surface area of the spherical impression made by a hardened steel ball, expressed in kgf/mm². Vickers and Brinell both use area, whereas Rockwell uses depth.

Question 9Engineering Materials

A material used for a spring must mainly possess

  1. high thermal expansion
  2. high resilience and fatigue resistance Correct answer.
  3. low elastic limit
  4. high electrical conductivity

Explanation

A spring must store elastic strain energy and recover it repeatedly, so it needs a high elastic limit, high resilience and good fatigue resistance, as obtained in spring steels. Conductivity and expansion are irrelevant to spring duty.

Question 10Engineering Materials

The chief purpose of normalising a steel component is to

  1. produce a fine, uniform grain structure and relieve internal stresses Correct answer.
  2. increase the carbon content of the surface
  3. produce maximum surface hardness by quenching in water
  4. soften the steel to the lowest possible hardness

Explanation

Normalising heats steel above the critical range and allows it to cool in still air, giving a finer and more uniform grain structure with moderate hardness and relieved stresses. It is not a surface treatment and does not aim at minimum hardness.

Question 11Engineering Materials

Which of the following non-ferrous alloys is most suitable for making bearing shells because it has good conformability and low friction?

  1. Babbitt metal Correct answer.
  2. Nichrome
  3. Muntz metal
  4. Duralumin

Explanation

Babbitt metal is a tin- or lead-base white bearing alloy that beds into the shaft easily, has low friction and good conformability, which is why it is used as a bearing lining. Duralumin is a structural aluminium alloy and Nichrome is a resistance-heating alloy.

Question 12Engineering Materials

A steel contains 0.8 per cent carbon and, on slow cooling, consists entirely of pearlite. Such a steel is called

  1. hypoeutectoid steel
  2. hypereutectoid steel
  3. eutectoid steel Correct answer.
  4. pure iron

Explanation

At about 0.8 per cent carbon, steel has the eutectoid composition, so on slow cooling austenite transforms completely into pearlite without free ferrite or cementite. Below this carbon level the steel is hypoeutectoid and above it hypereutectoid.

Question 13Engineering Materials

Which property is tested by the Izod or Charpy test?

  1. Resistance of a material to sudden impact loading Correct answer.
  2. Ability of a material to be bent through 180 degrees
  3. Electrical resistivity of a material
  4. Resistance of a material to scratching

Explanation

Izod and Charpy tests swing a heavy striker against a notched specimen and measure the energy absorbed in breaking it, which indicates impact toughness and the tendency towards brittle fracture. Scratch resistance and bend tests are separate evaluations.

Question 14Engineering Materials

A component must resist wear on its surface while remaining tough in the core. The most suitable treatment is

  1. full annealing
  2. stress relieving
  3. case carburising followed by hardening and tempering Correct answer.
  4. through hardening by quenching

Explanation

Case carburising enriches the surface in carbon so that, after hardening and tempering, the case is hard and wear-resistant while the low-carbon core stays tough. Through hardening makes the whole section hard and less tough in the core.

Question 15Engineering Materials

Two steels of the same carbon content are compared; steel A has a coarser pearlite spacing than steel B. Which statement is correct?

  1. Steel A will have higher ductility and lower strength than steel B
  2. Both steels will have identical strength because carbon content is the same
  3. Steel A will have higher strength and hardness than steel B
  4. Steel B will have higher strength and hardness than steel A Correct answer.

Explanation

Finer pearlite spacing restricts the movement of dislocations over shorter distances, so the strength and hardness increase; hence the finer-pearlite steel B is stronger. Carbon content alone does not fix strength, because the scale of the microstructure matters as well.

Question 16Engineering Materials

A steel shaft fails in service by fatigue. Which change in material or design is most directly effective in improving its fatigue life?

  1. Reducing the elastic limit of the steel
  2. Raising the sulphur content of the steel
  3. Introducing compressive residual stress at the surface by shot peening Correct answer.
  4. Increasing the surface roughness of the shaft

Explanation

Fatigue cracks usually start at the surface, so a compressive residual stress layer produced by shot peening suppresses crack initiation and lengthens fatigue life. A smoother surface and higher elastic limit also help, while the opposite changes are harmful.

Question 17Engineering Materials

Which of the following is the correct order of operations for producing a hardened and tempered steel component?

  1. Harden by quenching, then temper at a suitable temperature Correct answer.
  2. Temper, then harden, then cool in air
  3. Anneal, then temper, then harden
  4. Carburise, then anneal, then quench in oil without tempering

Explanation

Hardening by austenitising and quenching produces a hard but brittle martensitic structure, so tempering is carried out afterwards to reduce brittleness and develop the required combination of strength and toughness. Tempering before hardening would be pointless.

Question 18Engineering Materials

The approximate composition of 18-4-1 high speed steel is

  1. 18% carbon, 4% tungsten, 1% molybdenum
  2. 18% tungsten, 4% chromium, 1% vanadium Correct answer.
  3. 18% nickel, 4% tungsten, 1% silicon
  4. 18% chromium, 4% nickel, 1% carbon

Explanation

The standard 18-4-1 high speed steel contains about 18 per cent tungsten, 4 per cent chromium and 1 per cent vanadium, with roughly 0.7 per cent carbon. The tungsten and vanadium form hard carbides that retain hardness at the high temperatures of cutting.

Question 19Engineering Materials

Which of the following statements about the effect of increasing carbon content in plain carbon steel up to about 0.8 per cent is correct?

  1. Hardness decreases while toughness increases
  2. Tensile strength decreases while ductility increases
  3. Tensile strength and hardness increase while ductility decreases Correct answer.
  4. Both strength and ductility remain unchanged

Explanation

As carbon rises towards the eutectoid composition, the proportion of hard pearlite increases, so tensile strength and hardness rise while elongation and reduction in area fall. This is why high-carbon steels are strong but less ductile than mild steel.

Question 20Engineering Materials

A plain carbon steel is required for a component that must be soft, easily machined and subsequently formed by deep drawing. The most suitable carbon range is

  1. 2.5 to 3.5 per cent carbon
  2. 0.1 to 0.25 per cent carbon Correct answer.
  3. 0.9 to 1.2 per cent carbon
  4. 0.6 to 0.8 per cent carbon

Explanation

Low-carbon steels of about 0.1 to 0.25 per cent carbon are soft and ductile, so they machine and cold-form readily. Higher carbon raises strength and hardness but reduces the ductility needed for deep drawing.

Question 21Hand Tools and Work Bench Operations

In the First Year Basic Mechanical Engineering workshop, which hand tool is used to hold a job or a tool firmly during fitting work on the work bench?

  1. Ball peen hammer
  2. Scriber
  3. Vice Correct answer.
  4. Try square

Explanation

A bench vice is the standard work-holding device fixed to the work bench; its jaws grip the workpiece so that filing, sawing or chiselling can be done steadily. The other tools listed are marking or striking tools and cannot clamp a job.

Question 22Hand Tools and Work Bench Operations

The movable jaw of a bench vice is tightened by turning the handle, which rotates a threaded spindle. Which part of the vice does the spindle pass through to move the sliding jaw?

  1. The swivel base clamp
  2. The jaw plate serrations
  3. The anvil portion
  4. The fixed jaw nut Correct answer.

Explanation

The spindle thread engages a nut housed in the fixed jaw body; rotating the handle draws the sliding jaw towards the fixed jaw along the slide bars. The swivel base, jaw serrations and anvil do not convert handle rotation into jaw movement.

Question 23Hand Tools and Work Bench Operations

While filing a soft aluminium job held in a bench vice, the file repeatedly clogs between its teeth. Which action is most appropriate to continue the work correctly?

  1. Press the file harder against the job
  2. Clean the file with a file card and apply chalk to the teeth Correct answer.
  3. Strike the file on the vice to shake out chips
  4. Use the file on cast iron first to open the teeth

Explanation

Soft metals load the file teeth with chips, so the correct remedy is to clean the teeth with a file card (wire brush) and rub chalk on them to reduce pinning. Extra pressure worsens clogging, and striking the file can crack it because hardened files are brittle.

Question 24Hand Tools and Work Bench Operations

Which file is best suited for removing a large amount of metal quickly from a rough mild steel block during initial fitting?

  1. Second cut flat file
  2. Smooth cut flat file
  3. Needle file
  4. Rough cut flat file Correct answer.

Explanation

Files are graded by tooth pitch: rough files have coarse teeth for fast stock removal, second cut files for general work, and smooth files for finishing. A rough cut flat file therefore suits heavy initial reduction of a rough block.

Question 25Hand Tools and Work Bench Operations

A hacksaw blade is fitted in a hacksaw frame with the teeth pointing forward, away from the handle. What is the main reason for this orientation?

  1. It allows the blade to be reversed for thin sections
  2. Cutting occurs on the forward stroke, which allows a firmer, more controlled push Correct answer.
  3. It reduces the need for a wing nut on the frame
  4. It prevents the blade from bending during the return stroke

Explanation

Hacksaw blades are set to cut on the forward stroke, so the teeth must face away from the handle; the forward push is stronger and easier to control than the pull. Blade bending and wing nut fitting are not the reasons for tooth direction.

Question 26Hand Tools and Work Bench Operations

In a hacksaw, what is the function of the adjustable frame (as opposed to a fixed frame)?

  1. It converts the saw into a junior hacksaw
  2. It sets the amount of blade set
  3. It accepts blades of different standard lengths Correct answer.
  4. It changes the pitch of the blade teeth

Explanation

An adjustable frame can be lengthened or shortened so that blades of different standard lengths can be tensioned in it. Tooth pitch and tooth set are properties of the blade itself, and frame adjustment does not change these.

Question 27Hand Tools and Work Bench Operations

A chisel is being used to remove metal from a job held in a vice. Which safety precaution is most important for the person operating the chisel?

  1. Chisel towards yourself so the cut can be seen clearly
  2. Hold the chisel with the cutting edge towards the palm
  3. Wear goggles and direct the cut away from the body Correct answer.
  4. Use a chisel with a mushroomed head

Explanation

Chipping throws sharp metal chips, so eye protection is essential and the cut must be directed away from the operator and others nearby. Holding the edge towards the palm, cutting towards the body, or using a mushroomed head all create serious injury risks.

Question 28Hand Tools and Work Bench Operations

The point angle of a standard flat cold chisel used for cutting mild steel is approximately:

  1. 90 degrees
  2. 30 degrees
  3. 60 degrees Correct answer.
  4. 120 degrees

Explanation

A cold chisel for general metalwork is ground to about 60 degrees included angle, which balances edge strength and cutting ability for mild steel. Softer metals use a sharper angle and harder metals a blunter one.

Question 29Hand Tools and Work Bench Operations

Which tool is used with a scriber to guide straight lines parallel to the edge of a metal workpiece on a surface plate?

  1. Surface gauge with a scribing block Correct answer.
  2. Divider
  3. Centre punch
  4. Odd-leg caliper

Explanation

A surface gauge (scribing block) rides on a surface plate and its adjustable scriber point is set to a height so that parallel lines can be scribed on the work. A centre punch marks points, while odd-leg calipers and dividers are used for circles and centre location.

Question 30Hand Tools and Work Bench Operations

A centre punch is struck with a hammer before drilling a hole. What is the purpose of this operation?

  1. To harden the surface of the workpiece
  2. To enlarge the hole to the tapping size
  3. To remove the layout lines completely
  4. To create a small indentation that guides the drill point and prevents it from wandering Correct answer.

Explanation

The conical point of a centre punch produces a small dimple at the marked intersection, giving the drill a seat so it starts accurately instead of skidding. It does not size the hole, harden the metal, or erase layout lines.

Question 31Hand Tools and Work Bench Operations

Which marking tool is used to draw circles and arcs on a metal surface by setting the distance between two hardened points?

  1. Try square
  2. Vernier caliper
  3. Scriber
  4. Divider Correct answer.

Explanation

A divider has two pointed legs joined by a spring and adjusting screw; the point spacing is set to the required radius and one leg is pivoted to scribe circles or arcs. A try square checks angles, a vernier caliper measures, and a scriber draws straight lines.

Question 32Hand Tools and Work Bench Operations

A try square is placed against the edge of a workpiece to check squareness. If light is visible between the blade and the work along the whole length, what does this indicate?

  1. The try square blade is too long
  2. The edge is not square to the reference face Correct answer.
  3. The stock of the square is loose
  4. The workpiece is correctly square

Explanation

When a try square is held against a true reference face, its blade should contact the work evenly with no gap. A gap along the length shows the tested edge is out of square and must be corrected by filing or machining.

Question 33Hand Tools and Work Bench Operations

Which of the following is the correct way to hold a file while filing a flat surface?

  1. Both hands on the handle
  2. Both hands on the far end of the file
  3. One hand on the handle and the other on the far end of the file Correct answer.
  4. One hand on the handle with the file held vertically

Explanation

For flat filing the file is gripped with one hand on the handle and the other palm on the far end, so that even pressure is applied along the stroke and the surface stays flat. Holding it vertically or with both hands on one end prevents controlled, level strokes.

Question 34Hand Tools and Work Bench Operations

During cross filing of a flat surface, why is the file moved diagonally across the work and then the direction changed for the second pass?

  1. To avoid the need for a vice
  2. To prevent the file from becoming blunt
  3. To keep the surface flat and reveal high spots by the cross pattern Correct answer.
  4. To increase the cutting speed of the file teeth

Explanation

Cross filing in two diagonal directions produces a criss-cross pattern that shows where metal remains and helps keep the surface flat. The change of direction does not increase cutting speed, prevent bluntness, or replace work holding.

Question 35Hand Tools and Work Bench Operations

A hacksaw blade marked 18 TPI is selected instead of a 24 TPI blade. For which situation is the 18 TPI blade the better choice?

  1. Cutting thin-walled tubing where fine teeth are needed
  2. Cutting a thick solid section where chips must clear easily Correct answer.
  3. Cutting a very thin sheet held in a vice
  4. Cutting a small diameter rod of 5 mm

Explanation

Coarse teeth (lower TPI) have larger gullets that clear chips well and suit thick solid sections. Fine teeth are preferred for thin sections, tubing and small rods so that at least two or three teeth remain in contact with the work.

Question 36Hand Tools and Work Bench Operations

A file is described as a single cut file. How are its teeth formed?

  1. Random irregular knurling on the surface
  2. Two sets of diagonal cuts crossing each other
  3. Parallel rows of single diagonal cuts across the face Correct answer.
  4. Teeth raised by a milling cutter in straight lines

Explanation

A single cut file has one series of parallel diagonal cuts forming the teeth, giving a smooth shearing action suited to finishing and to soft metals. Double cut files have two crossing sets of cuts, and rasps have individual raised teeth.

Question 37Hand Tools and Work Bench Operations

While using a bench vice, why should a soft metal job be gripped between two pieces of soft sheet clamped in the jaws?

  1. To make the job sit at an angle
  2. To increase the gripping force of the vice
  3. To protect the finished surface from the serrated jaw plates Correct answer.
  4. To prevent the vice spindle from turning

Explanation

The hardened serrated jaw plates can indent and mark a finished or soft surface, so soft jaw clamps (often of copper or aluminium sheet) are used as protective packings. They do not increase gripping force or affect the spindle.

Question 38Hand Tools and Work Bench Operations

Which part of a bench vice provides a flat surface on which light hammering or riveting can be done?

  1. The handle ball end
  2. The swivel base plate
  3. The slide bars
  4. The anvil behind the fixed jaw Correct answer.

Explanation

Many bench vices have a small flat anvil formed on the body behind the fixed jaw for light hammering. The slide bars, swivel base and handle are functional parts not intended for striking work.

Question 39Hand Tools and Work Bench Operations

A scriber should not be used to mark a line across a machined finished surface without care. What is the main reason?

  1. Its hard sharp point can scratch and damage the finished surface Correct answer.
  2. It is too soft to mark metal
  3. It cannot be resharpened once blunt
  4. It is designed only for wood

Explanation

A scriber is made of hardened steel with a fine point, so it leaves a permanent scratch; on a finished surface this scratch may be unacceptable. The tool is hard, can be resharpened, and is intended for metal, so the concern is surface damage.

Question 40Hand Tools and Work Bench Operations

A cold chisel edge has become rounded and shiny after prolonged use on mild steel. What is the correct workshop remedy?

  1. Heat it red hot and quench it in water without grinding
  2. Continue using it with greater hammer force
  3. Sharpen it by rubbing on a wooden block
  4. Regrind the edge to the correct angle on a grinding machine and cool it frequently Correct answer.

Explanation

A dulled chisel is restored by grinding the cutting edge back to the correct angle, with frequent cooling in water to prevent the temper being drawn. Extra force cannot restore a rounded edge, and wood or simple quenching will not produce a sharp cutting edge.

Question 41Hand Tools and Work Bench Operations

Which work bench practice helps to prevent a vice from being strained or the bench from tipping when a long job is held?

  1. Hold the job with one hand while filing
  2. Support the overhanging end of the job with a bench stand Correct answer.
  3. Stand on the bench while filing
  4. Tighten the vice as hard as possible

Explanation

A long workpiece overhangs the vice and its weight can strain the vice and bench, so an adjustable bench stand is placed under the free end. Over-tightening, standing on the bench, or holding the job by hand does not provide proper support and may be unsafe.

Question 42Hand Tools and Work Bench Operations

What is the correct procedure when a hacksaw blade breaks during cutting and a new blade is to be fitted?

  1. Fit the new blade with teeth facing the handle and leave it slack
  2. Fit the new blade only after removing the frame from the job
  3. Fit the new blade with teeth facing forward and tension it firmly with the wing nut Correct answer.
  4. Fit the new blade and continue the same cut without checking alignment

Explanation

A replacement blade must be fitted with teeth pointing away from the handle and tensioned firmly by the wing nut so it cuts on the forward stroke without buckling. Slackness or reversed teeth cause poor cutting and breakage.

Question 43Hand Tools and Work Bench Operations

Which of these describes the correct use of a ball peen hammer when chipping with a cold chisel?

  1. Hold the hammer loosely at the very end and swing from the wrist only
  2. Use the ball face for all chipping blows
  3. Grip the handle near the head and strike with the ball face
  4. Grip the handle near its end and strike with the flat face, looking at the chisel edge Correct answer.

Explanation

For chipping, the hammer is gripped towards the end of the handle for leverage, the flat face is used, and the operator watches the chisel edge rather than the hammer head. Gripping near the head, using the ball face, or swinging from the wrist alone gives poor control.

Question 44Hand Tools and Work Bench Operations

During a fitting exercise, a student must check that two adjacent faces of a rectangular block are at exactly 90 degrees to each other. Which combination of tools gives the most direct check?

  1. Try square held against one face with its blade on the other face Correct answer.
  2. Centre punch and hammer
  3. Divider set to the block width
  4. Steel rule alone along each face

Explanation

A try square tests perpendicularity directly: the stock is held against one face and the blade against the adjacent face, and any gap shows error. A rule alone measures length, a divider transfers distances, and a punch marks points, so none checks squareness.

Question 45Fitting and Bench Work

In bench work, which file is used for general-purpose filing of mild steel with a double-cut face and a single-cut face?

  1. Half-round file
  2. Square file
  3. Triangular file
  4. Flat file Correct answer.

Explanation

A flat file has a rectangular section and is the standard general-purpose file for flat surfaces; its double-cut face removes metal quickly while the single-cut face gives a smoother finish. Half-round, triangular and square files are shaped for curved, internal-angle and square-slot work respectively.

Question 46Fitting and Bench Work

The safe edge of a file is provided so that the operator can:

  1. Hold the file without a handle
  2. Increase the depth of cut on soft metals
  3. File a surface without cutting an adjacent shoulder Correct answer.
  4. Measure the length of stroke

Explanation

One or two edges of a file are left uncut (safe) so that when filing up to a shoulder or inside a corner the adjacent finished surface is not damaged. The toothed edges are the cutting edges, and the safe edge has no teeth.

Question 47Fitting and Bench Work

The grade of a file refers to:

  1. The length of the file body
  2. The shape of the file section
  3. The hardness of the file handle
  4. The spacing of the teeth (coarseness of cut) Correct answer.

Explanation

File grade describes tooth spacing: rough, bastard, second cut and smooth, from coarsest to finest. Length, section shape and handle material are separate characteristics and do not define the grade.

Question 48Fitting and Bench Work

Which bench vice part is tightened to clamp the workpiece between the jaws?

  1. The anvil through the set screw
  2. The swivel base through the locking bolt
  3. The fixed jaw through the base plate
  4. The movable jaw through the handle and screw Correct answer.

Explanation

In a bench vice the fixed jaw is part of the body and the movable jaw slides on the slide bar, being drawn forward by the screw when the handle is turned. The swivel base only changes the working angle and the anvil is used for light hammering.

Question 49Fitting and Bench Work

The hacksaw blade is mounted in the frame with the teeth pointing:

  1. Either way, since the direction does not matter
  2. Backward, toward the handle
  3. Upward, away from the workpiece
  4. Forward, away from the handle Correct answer.

Explanation

Hacksaw teeth are set to cut on the forward stroke, so the blade is fitted with the points facing away from the handle. Fitting it backward means the blade rubs on the return stroke and cuts poorly.

Question 50Fitting and Bench Work

In a vernier caliper, the least count when the main scale has 1 mm divisions and the vernier has 50 divisions is:

  1. 0.05 mm
  2. 0.1 mm
  3. 0.02 mm Correct answer.
  4. 0.5 mm

Explanation

Least count equals the value of one main scale division divided by the number of vernier divisions, so 1 mm / 50 = 0.02 mm. A 20-division vernier would give 0.05 mm and a 10-division vernier 0.1 mm.