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Past Questions
A machine used to bore holes in large and heavy parts such as engine frame, steam engine cylinders, machine housing etc. is
A)
Grinding machine
B)
Boring machine
C)
Planing machine
D)
Milling machine
A boring machine is specifically used to enlarge or accurately finish existing holes in large and heavy workpieces such as engine frames, steam engine cylinders, and machine housings. Grinding is for surface finishing, planing is for flat surfaces, and milling is for removing material using a rotating cutter, not primarily for boring large holes.
The Equilibrium diagrams of alloys indicate the following
A)
Temperature at which the solid alloy will start melting & finish melting
B)
Possible phase changes which will occur as the result of altering the composition or temperature
C)
The percentage of increase of melting temperature of alloy
D)
Both (a) & (b)
Equilibrium (phase) diagrams of alloys show the stable phases present at different temperatures and compositions. From such diagrams, we can determine the temperatures at which a solid alloy starts melting (solidus line) and finishes melting (liquidus line). They also indicate possible phase changes that occur when composition or temperature is varied. Option (c) is incorrect because equilibrium diagrams do not show the percentage increase of melting temperature.
The length, breadth and depth of a water container is 3m, 2m and 1m respectively, the volume is
A)
600 litres
B)
3000 litres
C)
2000 litres
D)
None of these
Volume of a rectangular container = length × breadth × depth = 3 m × 2 m × 1 m = 6 cubic metres. Since 1 cubic metre = 1000 litres, 6 cubic metres = 6000 litres. So the correct calculation gives 6000 litres, which is not among options (a), (b), or (c). Therefore the correct option is (d) None of these.
The maximum and minimum pressure in a plate clutch where the axial force is 1000 lb (the inside radius of contact is Ri = 2 in, the outside radius is Ro = 4 in) is 39.8 psi and 19.9 psi respectively. If uniform wear is assumed, the Average pressure is
A)
29.85 psi
B)
26.5 psi
C)
19.9 psi
D)
None of these
For a plate clutch under the uniform wear assumption, pressure varies inversely with radius, so the pressure is maximum at the inner radius and minimum at the outer radius. The average pressure may be taken as the mean of maximum and minimum pressures:
Average pressure = (p_max + p_min) / 2
= (39.8 + 19.9) / 2
= 59.7 / 2
= 29.85 psi.
So the correct answer is 29.85 psi. Option (c) is only the minimum pressure, and option (b) does not match the correct average value.
The main rotating parts which are to be balanced mechanically are
A)
Inlet valve & outlet valve
B)
Piston & Piston ring
C)
Crankshaft & Flywheel
D)
None of these
Mechanical balancing is mainly required for rotating parts to reduce vibration and dynamic forces. In an engine, the crankshaft and flywheel are the principal rotating components that must be balanced. The inlet valve and outlet valve are not rotating parts, and the piston and piston ring have reciprocating motion rather than being main rotating parts. Hence, the correct answer is Crankshaft & Flywheel.
The permissible maximum value of operating temperature for metal on metal material for the Brake is
A)
300°F
B)
400°F
C)
500°F
D)
600°F
For brake friction materials, the permissible maximum operating temperature for metal-on-metal braking surfaces is generally taken as 500°F. This is the standard upper limit among the given options. 300°F and 400°F are too low for the maximum permissible value, while 600°F exceeds the usual safe operating limit.
Grease cannot be used as a lubricant for the lubrication of
A)
Front wheel bearings
B)
Input shaft
C)
Coolant pump
D)
Transmission
Grease is generally used where lubricant should stay in place, such as front wheel bearings. A coolant pump and input shaft may also use grease in certain bearing applications. However, a transmission requires oil, not grease, because it contains gears that need continuous circulation and cooling. Grease cannot flow and lubricate the gear teeth properly, so it is not used for transmission lubrication.
Which of the following statement is true?
A)
Worm gearing is widely used to transmit power at high velocity ratios between non-intersecting shafts that are usually, but not necessarily, at right angles
B)
Spur gearing is widely used to transmit power at high velocity ratios between non-intersecting shafts that are usually, but not necessarily, at right angles
C)
Vee belt is widely used to transmit electrical power
D)
None of these
Worm gears are used for transmitting power between non-intersecting shafts, generally at right angles, and they can provide very high velocity ratios. Spur gears, on the other hand, are used between parallel shafts, not non-intersecting shafts, so option (b) is false. A Vee belt is used for power transmission in machines, not specifically for transmitting electrical power, so option (c) is false. Therefore, the correct statement is option (a).
Which are widely used length standards?
A)
Kilometre & furlong
B)
International standard metre & Imperial standard yard
C)
Centimetre & inch
D)
None of these
The widely used length standards in metrology are the International Standard Metre and the Imperial Standard Yard. These are recognized reference standards for measuring length. The other options list common units of length, but not standard reference standards. Therefore, option (b) is correct.
The measuring devices, which enable the position of a surface to be determined with respect to horizontal and are widely used for the static levelling of machinery and other equipment are
A)
Spirit levels
B)
Angle gauges
C)
Bevel protractor
D)
Sine bar
Spirit levels are measuring devices used to determine the position of a surface with respect to the horizontal. They are widely used for static levelling of machinery and other equipment. Angle gauges, bevel protractor, and sine bar are used for angle measurement, not for direct levelling.
The device for smoothing out the power impulses from the engine is called
A)
Clutch
B)
Differential
C)
Flywheel
D)
Torque converter
A flywheel stores excess energy during the power stroke and releases it during the non-power strokes, thereby smoothing out the fluctuations in engine torque and power output. A clutch only connects and disconnects power transmission, a differential allows wheels to rotate at different speeds, and a torque converter transmits and multiplies torque in automatic transmissions.
Flat belts and V-belts may be employed
A)
to transmit mechanical power from one shaft to electrical power
B)
to transmit power from one shaft to another where it is not necessary to maintain an exact speed ratio between the two shafts
C)
to stop the engine
D)
None of these
Flat belts and V-belts are used for power transmission between shafts. They are suitable where a small amount of slip and creep is acceptable, so an exact speed ratio is not essential. Option (a) is incorrect because belts do not transmit mechanical power directly into electrical power. Option (c) is incorrect because stopping an engine is not the function of belts. Therefore, the correct choice is (b).
The ratio between the ultimate tensile stress and the working stress is called
A)
Poisson’s ratio
B)
Factor of safety
C)
Strength of material
D)
None of these
The factor of safety is defined as the ratio of ultimate stress (or ultimate tensile stress) to working stress (or allowable/working stress). So, ultimate tensile stress ÷ working stress = factor of safety. Poisson’s ratio is the ratio of lateral strain to longitudinal strain, so option (a) is incorrect. Option (c) is not a standard term for this ratio, and (d) is therefore also incorrect.
Cutting work of iron and steel with the aid of oxygen which is extensively used nowadays in industry is
A)
Oxygen cutting
B)
Arc cutting
C)
Electric cutting
D)
None of these
Cutting iron and steel with the aid of oxygen is known as oxygen cutting or oxy-fuel cutting. It is widely used in industry for cutting ferrous metals. Arc cutting and electric cutting are different processes and do not specifically refer to cutting with oxygen.
The operation of removing trapped air from hydraulic braking system is known as
A)
Tapping
B)
Trapping
C)
Bleeding
D)
Pressurization
In a hydraulic braking system, trapped air must be removed because air is compressible and reduces braking efficiency. The process of expelling this air is called bleeding. Tapping, trapping, and pressurization are not the standard term for this operation.
Which of the following does not form a part of equipments which are commonly used for electric arc welding?
A)
Electrode
B)
Gas
C)
AC or DC machine
D)
Cable lug
In electric arc welding, the essential equipment includes an electrode, an AC or DC welding machine (power source), and cables/cable lugs for current flow. Gas is not a common part of basic electric arc welding equipment; it is associated with gas welding or some gas-shielded welding processes, not ordinary arc welding.
For balancing single cylinder engine, a counter weight is added to
A)
Gudgeon pin
B)
Piston
C)
Connecting rod
D)
Crankshaft
In a single-cylinder engine, the reciprocating and rotating masses create unbalanced forces. To reduce this, a counterweight is provided on the crankshaft, especially on the crank webs, to balance the rotating parts and partially balance the reciprocating parts. A counterweight is not added to the piston, gudgeon pin, or connecting rod for this purpose.
Which one is not type of belts?
A)
Flat belt
B)
Circular belt or rope
C)
Vee belt
D)
Chain
Belts are flexible power-transmission elements. Common types include flat belt, circular belt (rope), and V-belt (vee belt). A chain is not a belt; it is a chain drive element used in positive transmission systems.
The machine element which provides a convenient means for transforming rotary motion into reciprocating motion is
A)
Spur gear
B)
Spring
C)
Cam
D)
None of these
A cam is a machine element designed to convert rotary motion into reciprocating or oscillating motion through direct contact with a follower. Spur gears transmit rotary motion between shafts, and springs store energy or provide force, but neither is used for this motion conversion. Hence, the correct answer is Cam.
Heat treatment refers to a combination of processing of a metal or alloy in the solid state for the purpose of obtaining desired properties
A)
Balancing & Wiring
B)
Heating & Cooling
C)
Welding & Lighting
D)
None of these
Heat treatment is the controlled heating and cooling of a metal or alloy in the solid state to obtain desired properties such as hardness, strength, ductility, or toughness. Options like balancing/wiring or welding/lighting are unrelated to the definition. Therefore, the correct answer is Heating & Cooling.
___ is generally done to improve machinability of steel.
A)
Tempering
B)
Annealing
C)
Normalising
D)
Cyaniding
Annealing is generally done to improve the machinability of steel because it softens the metal, reduces hardness, and relieves internal stresses. This makes cutting and shaping easier. Tempering is mainly used to reduce brittleness after hardening, normalising is used to refine grain structure and improve uniformity, and cyaniding is a case-hardening process, not a machinability-improving treatment.
In one operation of high speed steel, the operation should be carried out at
A)
900 to 1100°C
B)
1100 to 1360°C
C)
1300 to 1500°C
D)
None of these
High speed steel is used for cutting tools that retain hardness at elevated temperatures. In operation, it is generally used at red-hot cutting temperatures, roughly around 900 to 1100°C. This range is suitable for high-speed machining because HSS maintains sufficient hardness due to its high hot hardness. The higher ranges in options (b) and (c) are beyond the practical operating temperature for HSS and would cause excessive softening and tool failure.
A metal cannot exist in the
A)
Gaseous state
B)
Liquid state
C)
Solid state
D)
None of these
Metals are generally found in the solid state at ordinary conditions, and some can also exist in the liquid state when melted. In basic material science, metals are not considered to exist in the gaseous state under normal conditions because metallic bonding is not retained as a stable bulk phase there. Therefore, the correct answer is gaseous state. Liquid and solid states are both possible for metals, so options (b) and (c) are incorrect.
Which of the following is not basic area of inspection?
A)
Receiving inspection
B)
Final inspection
C)
Inprocess inspection
D)
Production
Basic areas of inspection include receiving inspection, in-process inspection, and final inspection. These are standard stages where quality is checked before, during, and after manufacturing. Production is a manufacturing activity, not an inspection area. Hence, the correct answer is Production.
Which of the following does not form part of the effects which were obtained by Annealing process?
A)
Soften the steel
B)
Relieve internal stresses
C)
Improve machinability
D)
None of these
Annealing is a heat treatment process used to soften steel, relieve internal stresses, and improve machinability. Since all options (a), (b), and (c) are effects of annealing, none of them is excluded. Therefore, the correct answer is (d) None of these.