Workshop viva questions and answers are presented below with respect to Cycle 1 and Cycle 2.
Cycle 1 consists of four trades: Fitting, Welding, Foundry, and Machine Shop.
Cycle 2 also consists of four trades: Carpentry, Tinsmithy, House Wiring, and Power Tools.
The viva questions and answers for both Cycle 1 and Cycle 2 are provided below.
Workshop Viva Questions and Answers
Cycle-I
FITTING
What is fitting?
Fitting is a manufacturing process of shaping and assembling metal parts using hand tools to achieve the desired size and finish.
Sequence of operations to be performed in fitting shop
Marking → Cutting → Filing → Drilling → Reaming → Tapping → Finishing → Inspection.
What are the work holding tools?
Bench vice, hand vice, machine vice, clamps, V-blocks, and angle plates.
What are the measuring and marking tools used in fitting shop?
Steel rule, Vernier caliper, micrometer, try-square, scriber, divider, surface plate, and marking gauge.
What are the cutting tools used in fitting?
Hacksaw, chisel, files, drills, reamers, taps, and dies.
What are the finishing tools used in fitting?
Files (smooth, bastard), emery paper, polishing tools.
What are the striking tools used in fitting?
Ball peen hammer, cross peen hammer, mallet.
What is the use of Try-Square?
It is used to check the squareness (90° angle) and to mark right angles on a workpiece.
Difference between Dot punch and Center punch
Dot punch is used for light marking with a small indentation. Center punch is used to make deeper marks to guide drilling.
Methods of Filing
Straight filing, cross filing, draw filing, and diagonal filing.
Safety precautions to be taken in fitting shop
Use proper tools, ensure tight clamping of workpiece, wear goggles, avoid excessive force, and keep tools in good condition.
WELDING
What is Welding?
Welding is a process of joining two or more metal parts by heating them to a suitable temperature with or without pressure and filler material.
Name few welding processes
Arc welding, gas welding, TIG welding, MIG welding, spot welding.
Essential tools and equipment used in welding
Welding machine, electrodes, welding cables, electrode holder, chipping hammer, wire brush, safety helmet, gloves.
Safety precautions in welding
Wear welding helmet and gloves, ensure proper ventilation, avoid direct exposure to arc light, keep flammable materials away.
Types of Weld joints
Butt joint, lap joint, corner joint, edge joint, T-joint.
Materials required for welding process
Base metal, filler rod/electrode, flux, shielding gas (in some processes).
Sequence of operations in welding process
Preparation of joint → Cleaning → Setting → Welding → Cooling → Inspection → Finishing.
Difference between Arc welding and Gas welding
Arc welding uses electric arc as heat source, while gas welding uses flame (oxygen + acetylene). Arc welding is faster; gas welding is slower but gives better control.
Name common welding defects
Porosity, cracks, slag inclusion, undercut, incomplete fusion.
FOUNDRY (SAND MOULDING)
What is foundry?
Foundry is a place where metal casting is done by melting metal and pouring it into molds.
Explain the foundry process / sand moulding process
Pattern preparation → Mould making → Core making → Melting → Pouring → Cooling → Shakeout → Cleaning → Inspection.
Tools and equipment used in foundry
Flask, trowel, riddle, rammer, sprue pin, vent wire, ladle.
Safety precautions to be taken in foundry
Wear heat-resistant PPE, avoid moisture in molds, handle molten metal carefully, maintain safe distance.
Properties of Moulding Sand
Permeability, strength, plasticity, refractoriness, adhesiveness, cohesiveness.
Kinds of Moulding Sand
Green sand, dry sand, loam sand, facing sand, core sand.
What is pattern and its types?
Pattern is a replica of the casting used to prepare mold cavity. Types include solid pattern, split pattern, match plate pattern, sweep pattern.
What is the use of Sprue and Riser?
Sprue allows molten metal to enter the mold; riser supplies extra metal to compensate shrinkage.
What is the use of core in sand moulding process?
Core is used to create internal cavities or hollow sections in casting.
What is mould cavity?
It is the hollow space formed in the mold which takes the shape of the final casting.
Difference between Solid pattern and Split pattern
Solid pattern is made in one piece; split pattern is divided into two halves for easy removal.
What is the use of strike-off bar in moulding process?
It is used to remove excess sand and level the mold surface.
What is the use of parting sand?
It prevents sticking between mold halves and pattern.
What is pattern and how it is different from casting?
Pattern is the model used to make the mold, while casting is the final metal product obtained after solidification.
MACHINE SHOP
What is a Lathe machine and its uses?
A lathe machine rotates the workpiece against a cutting tool to perform operations like turning, facing, drilling, and threading.
Main parts of Lathe machine
Bed, headstock, tailstock, carriage, spindle, chuck, tool post.
Difference between facing and turning operation
Facing produces a flat surface at the end of the workpiece; turning reduces diameter along the length.
Purpose of chuck and name its types
Chuck holds the workpiece. Types include three-jaw chuck, four-jaw chuck, collet chuck.
Difference between Turning, Taper Turning and Step turning
Turning produces uniform diameter, taper turning produces conical shape, step turning produces different diameters in steps.
Safety operations to be taken in machine shop
Wear proper clothing, avoid loose items, ensure proper clamping, keep hands away from rotating parts, follow instructions.
Lathe operations:
Facing
Produces a flat surface at the end of the workpiece.
Turning
Reduces the diameter of a rotating workpiece.
Step Turning
Produces different diameters along the length.
Taper Turning
Produces a conical shape on the workpiece.
Thread Cutting
Creates external or internal threads.
Knurling
Produces a rough patterned surface for better grip.
Drilling
Makes a hole along the axis using a drill.
Boring
Enlarges an already drilled hole.
Reaming
Finishes a hole to accurate size and smooth surface.
Grooving
Cuts a narrow groove on the workpiece.
Chamfering
Removes sharp edges by making a bevel.
Polishing
Improves surface finish using abrasives.
Workshop Viva Questions and Answers
Cycle-II
CARPENTRY
Application of carpentry?
Carpentry is used for making furniture, doors, windows, roofs, cabinets, wooden structures, and interior decorations in buildings.
Types of joints in carpentry?
Common joints include butt joint, lap joint, mortise and tenon joint, dovetail joint, bridle joint, and tongue and groove joint.
Measuring tools used in carpentry?
Measuring tools include steel rule, measuring tape, try square, calipers, and folding rule.
Marking tools used in carpentry?
Marking tools include marking gauge, pencil, scriber, try square, and marking knife.
Finishing tools used in carpentry?
Finishing tools include plane, sandpaper, scraper, file, and polishing tools.
Cutting tools used in carpentry?
Cutting tools include hand saw, chisel, plane cutter, and circular saw.
Types of files used in carpentry?
Files used include flat file, round file, half-round file, and rasp file.
Types of chisels used in carpentry?
Common chisels include firmer chisel, bevel edge chisel, mortise chisel, and paring chisel.
Safety precautions to be taken in carpentry?
Wear safety goggles, keep tools sharp and clean, use proper tools, maintain correct posture, and keep the workplace clean.
Which type of hammer is used for extracting nails from wood?
A claw hammer is used to extract nails from wood.
TINSMITHY
How can you measure the thickness of a sheet (galvanized iron sheet)?
Thickness is measured using a micrometer screw gauge or vernier caliper.
What are the cutting tools used in tinsmithy?
Cutting tools include snips, shears, hacksaw, and chisels.
What are the forming/shaping tools used in tinsmithy?
Forming tools include stakes, hammers, mallets, and rollers.
What are the striking tools used in tinsmithy?
Striking tools include ball peen hammer, mallet, and riveting hammer.
What are the marking tools used in tinsmithy?
Marking tools include scriber, divider, try square, and steel rule.
What are the measuring tools used in tinsmithy?
Measuring tools include steel rule, calipers, vernier caliper, and micrometer.
Types of snips?
Types of snips include straight snips, left-hand snips, right-hand snips, and curved snips.
What is development of a surface in tinsmithy with respect to galvanized sheet?
It is the process of unfolding or laying out a 3D object into a flat pattern on a sheet before cutting and forming.
POWER TOOLS
How are power tools different from conventional tools?
Power tools operate using electricity or batteries and require less manual effort, whereas conventional tools are manually operated and require more physical effort.
Name a few power tools.
Examples include electric drill, angle grinder, circular saw, jigsaw, and power sander.
Applications of power tools in household and industrial applications?
In households, they are used for drilling, cutting, and repairs; in industries, they are used for manufacturing, construction, and heavy-duty operations.
HOUSE WIRING
Difference between series and parallel connection?
In series connection, components are connected end-to-end and current is the same through all; in parallel connection, components are connected across the same voltage and current divides among them.
What are the types of wires used in electrical wiring?
Types include PVC insulated wires, VIR wires, TRS cables, and flexible wires.
Difference between fuse and circuit breaker?
A fuse melts and breaks the circuit when excess current flows, while a circuit breaker automatically trips and can be reset.
Symbols of electrical and electronic systems/components?
Symbols represent components like resistor, capacitor, diode, switch, battery, and ground in circuit diagrams.
What is earthing?
Earthing is the process of connecting electrical equipment to the ground to prevent electric shock and ensure safety.
Types of fuses?
Types include rewirable fuse, cartridge fuse, HRC fuse, and thermal fuse.
What are the applications of staircase wiring?
It is used to control a single light from two different locations, such as staircases and corridors.
Difference between conductor and insulator?
Conductor
A conductor is a material that allows electric current to pass through it easily due to the presence of free electrons.
Examples: Copper, Aluminum, Silver
Insulator
An insulator is a material that does not allow electric current to pass through it easily because it has very few or no free electrons.
Examples: Rubber, Glass, Plastic
END of Workshop Viva Questions and Answers
Elements of Mechanical Engineering for III Year - Viva Questions and Short Answers
Basic Mechanical Engineering "Short Answers (SAQ/LAQ)"
Unit I:
- Derivation of Carnot cycle.
- Derivation of Otto cycle.
- Derivations for the applications of First law of Thermodynamics - Const. Volume, Const. Pressure, Const. Temperature process.
- Explain the working of 4-stroke SI Engine?
- Explain the working of 4-Stroke CI Engine?
- Explain the working of Babcock and Wilcox boiler with neat sketch?
- Explain the working of Cochran boiler with neat sketch?
- Explain the working of Francis Turbine with neat sketch?
- Explain the working of Kaplan Turbine with neat sketch?
- Explain the working of Vapor compression refrigeration cycle with neat sketch?
- Explain the working of Vapor Absorption refrigeration cycle with neat sketch?
Basic Mechanical Engineering "Viva Questions and Short Answers"
Unit I
1. List Energy Resources.
Energy resources are broadly classified as renewable and non-renewable.
Renewable sources include solar, wind, hydro, biomass, and geothermal energy.
Non-renewable sources include coal, petroleum, natural gas, and nuclear fuels.
2. What is the use of surge tank in hydroelectric power plant?
A surge tank is provided in a hydroelectric plant to control pressure variations in the penstock. It protects the pipeline from water hammer effects caused by sudden load changes. It also stabilizes the flow of water to the turbine.
3. Define System, Boundary, Surroundings.
- A system is a defined quantity of matter or region selected for study.
- The boundary is the real or imaginary surface separating the system from surroundings.
- Everything outside the boundary is called surroundings.
4. Define closed, open and isolated system.
- A closed system allows energy transfer but not mass transfer across its boundary.
- An open system permits both mass and energy transfer.
- An isolated system allows neither mass nor energy exchange.
5. Difference between intensive and extensive properties
Intensive properties do not depend on the quantity of matter, such as temperature and pressure.
Extensive properties depend on the mass of the system, such as volume and energy. Extensive properties change with system size, while intensive ones remain constant.
6. Difference between diathermic and adiabatic process.
In a diathermic process, heat transfer between system and surroundings is allowed.
In an adiabatic process, no heat transfer occurs across the boundary. Adiabatic processes are usually well insulated.
7. Difference between pump and turbine.
A pump converts mechanical energy into fluid energy to increase pressure.
A turbine converts fluid energy into mechanical work. Pumps require external power, whereas turbines produce power.
8. State Zeroth law of thermodynamics.
The Zeroth law states that if two systems are each in thermal equilibrium with a third system, they are in thermal equilibrium with each other. This law forms the basis for temperature measurement.
9. State First law of thermodynamics.
The First law states that energy cannot be created or destroyed, only transformed. For a closed system, heat added equals the increase in internal energy plus work done. It represents conservation of energy.
10. Second law of thermodynamics – Clausius and Kelvin-Planck statements
Clausius statement says heat cannot flow spontaneously from a colder body to a hotter body.
Kelvin-Planck statement says no heat engine can convert all heat into work in a cycle. Both statements express limitations on energy conversion.
Unit II
1. Define Heat Engine
A heat engine is a device that converts thermal energy into mechanical work. It operates between a high temperature source and a low temperature sink. It works on a thermodynamic cycle.
2. List components of Heat Engine
The main components are a heat source, working substance, heat sink, and mechanical output device. The working substance absorbs heat and produces work. The sink receives the rejected heat.
3. What is TDC and BDC?
TDC (Top Dead Centre) is the highest position of the piston inside the cylinder.
BDC (Bottom Dead Centre) is the lowest position of the piston. These positions define the piston stroke length.
4. What is clearance volume?
Clearance volume is the space remaining in the cylinder when the piston is at TDC. It prevents mechanical contact between piston and cylinder head. It also influences compression ratio.
5. List performance parameters of engine
Common performance parameters include indicated power, brake power, mechanical efficiency, and thermal efficiency. Specific fuel consumption and mean effective pressure are also important. These parameters evaluate engine efficiency and output.
6. Difference between air cooling and water cooling
Air cooling uses air flow to remove engine heat directly from fins.
Water cooling uses circulating coolant to absorb and carry away heat. Water cooling provides better temperature control than air cooling.
7. List properties of lubricant
Lubricants should have suitable viscosity, high flash point, and low pour point. They must resist oxidation and prevent corrosion. Good lubricants reduce friction and wear.
8. Define boiler and classify them
A boiler is a closed vessel in which water is converted into steam by heating. Boilers are classified as fire-tube and water-tube types. They can also be classified based on pressure and circulation method.
9. List boiler mountings and accessories
Boiler mountings include safety valve, pressure gauge, water level indicator, and stop valve.
Boiler Accessories include economizer, superheater, and air preheater. Mountings ensure safety, while accessories improve efficiency.
10. Difference between impulse and reaction turbine
In an impulse turbine, water pressure remains constant across the runner.
In a reaction turbine, pressure changes as water flows through the blades. Impulse turbines use high velocity jets, while reaction turbines use pressure energy.
Unit III
1. What is a centrifugal pump?
A centrifugal pump is a hydraulic machine that increases fluid pressure using centrifugal force. It consists of an impeller rotating inside a casing. It is widely used for water supply and irrigation.
2. What is a Pelton turbine?
A Pelton turbine is an impulse turbine used for high head applications. It uses water jets striking bucket-shaped blades. It converts kinetic energy of water into mechanical energy.
3. Use of braking jet in Pelton turbine
The braking jet is used to stop the runner quickly during shutdown. It directs a jet opposite to the rotation direction. This reduces stopping time and improves safety.
4. Applications of Pelton turbine
- Pelton turbines are used in high head, low discharge hydroelectric plants.
- They are suitable for mountainous regions.
- They are commonly installed in small and medium hydro projects.
5. What is a Kaplan turbine?
A Kaplan turbine is a reaction turbine used for low head and high flow conditions. It has adjustable blades for better efficiency. It operates similar to a propeller.
6. Difference between Kaplan and Francis turbine
- Kaplan turbine is used for low head and high discharge conditions.
- Francis turbine is used for medium head applications.
- Kaplan has adjustable runner blades, while Francis has fixed blades.
7. Define Refrigerant
A refrigerant is a working fluid used in refrigeration systems. It absorbs heat at low temperature and pressure and releases it at high temperature. It undergoes phase change during the cycle.
8. Define One Ton of Refrigeration
One ton of refrigeration is the cooling effect required to freeze one ton of water into ice in 24 hours. It is equal to 3.517 kW of cooling capacity. It represents the rate of heat removal.