Official Paper

SSC JE CBT-II (Mechanical Engineering) Official Paper (Held On 07 Apr, 2026) (Previous Year Paper)

100 questions · 120 minutes · with answers · free

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General Engineering (100 questions)

Hooke's law is valid in which material deformation region?

((a))
Plastic
((b))
Elastic
((c))
Brittle
((d))
Viscoelastic

Show Answer

Answer: ((a))

Plastic

Which of the following quantities is expressed without any unit?

((a))
Young's Modulus
((b))
Stress
((c))
Strain
((d))
Yield point

Show Answer

Answer: ((a))

Young's Modulus

What is the formula for Modulus of Rigidity?

((a))
Ratio of shear stress to shear strain
((b))
Ratio of ultimate stress to permissible stress
((c))
Ratio of tensile stress to tensile strain
((d))
Ratio of force to unit area

Show Answer

Answer: ((a))

Ratio of shear stress to shear strain

During a tensile test on ductile material, necking begins at which stage?

((a))
Yield point
((b))
Ultimate tensile strength
((c))
Elastic limit
((d))
Breaking point

Show Answer

Answer: ((a))

Yield point

A 2 m long steel rod with 20 mm diameter experiences 40 kN axial tensile load. Given that E = 200 GPa, the rod's elongation is approximately:

((a))
0.13 mm
((b))
0.25 mm
((c))
0.33 mm
((d))
1.27 mm

Show Answer

Answer: ((a))

0.13 mm

The ability of a material to absorb energy before fracture defines which of the following properties:

((a))
Toughness
((b))
Resilience
((c))
Hardness
((d))
Plasticity

Show Answer

Answer: ((a))

Toughness

A bar under 250 MPa engineering stress and 0.20 engineering strain has what true stress value?

((a))
100 MPa
((b))
300 MPa
((c))
350 MPa
((d))
400 MPa

Show Answer

Answer: ((a))

100 MPa

A thin-walled spherical shell has an internal diameter of d, which is exposed to an internal pressure p. If $\sigma_t$ represents the tensile stress of the shell's material, then the shell's thickness (t) can be determined as:

((a))
$p.d/\sigma_t$
((b))
$p.d/3\sigma_t$
((c))
$p.d/2\sigma_t$
((d))
$p.d/4\sigma_t$

Show Answer

Answer: ((a))

$p.d/\sigma_t$

A thick cylinder with an internal diameter of d and an external diameter of 2d is exposed to an internal pressure p. The maximum hoop stress that occurs in the cylinder is then:

((a))
$\frac{2}{3}p$
((b))
p
((c))
$\frac{5}{3}p$
((d))
2p

Show Answer

Answer: ((a))

$\frac{2}{3}p$

The frictional torque in a flat pivot bearing under uniform pressure distribution is given by:

((a))
$\frac{1}{2}(\mu \times W \times R)$
((b))
$\frac{2}{3}(\mu \times W \times R)$
((c))
$\frac{3}{4}(\mu \times W \times R)$
((d))
$(\mu \times W \times R)$

Show Answer

Answer: ((a))

$\frac{1}{2}(\mu \times W \times R)$

The friction torque developed in a cone clutch under axial load is mathematically identical to which bearing type?

((a))
Trapezoidal pivot bearing
((b))
Flat collar bearing
((c))
Conical pivot bearing
((d))
Flat pivot bearing

Show Answer

Answer: ((a))

Trapezoidal pivot bearing

For roller chain drives, the chain pitch 'p' connects to the sprocket's pitch circle diameter 'd' (with T teeth) via this geometric relation:

((a))
$P = d \sin(180^{\circ}/T)$
((b))
$P = d \sin(60^{\circ}/T)$
((c))
$P = d \sin(90^{\circ}/T)$
((d))
$P = d \sin(120^{\circ}/T)$

Show Answer

Answer: ((a))

$P = d \sin(180^{\circ}/T)$

For maximum power transmission in a belt drive, the condition is:

((a))
$T_{max} = mv^2$
((b))
$T_{max} = 3mv^2$
((c))
$T_{max} = \frac{T_1+T_2}{2}$
((d))
$T_{max} = 3T_1$

Show Answer

Answer: ((a))

$T_{max} = mv^2$

In a centrifugal clutch, if the operational engagement speed needs to be doubled, what should be the incremental factor for the number of shoes?

((a))
1
((b))
0.5
((c))
4
((d))
2

Show Answer

Answer: ((a))

For a disc clutch with n1 discs on the driving shaft and n2 on the driven shaft, the number of contact surface pairs is:

((a))
n₁ + n₂
((b))
n₁ - n₂
((c))
n₁ + n₂ + 1
((d))
n₁ + n₂ - 1

Show Answer

Answer: ((a))

n₁ + n₂

Calculate the power delivered by a belt drive operating at a linear speed of 10 m/s, where the tension on the tight side is 2500 N and the tension on the slack side is 800 N.

((a))
17 kW
((b))
19 kW
((c))
20 kW
((d))
21 kW

Show Answer

Answer: ((a))

17 kW

What is the total length L of a belt in an open belt drive connecting two pulleys of diameters d1 and d2 with a center distance x?

((a))
$\frac{\pi}{2}(d_1 - d_2) + 2x + \frac{(d_1 + d_2)^2}{4x}$
((b))
$\frac{\pi}{2}(d_1 + d_2) + 2x + \frac{(d_1 - d_2)^2}{4x}$
((c))
$\frac{\pi}{2}(d_1 - d_2) + 2x + \frac{(d_1 - d_2)^2}{4x}$
((d))
$\frac{\pi}{2}(d_1 + d_2) + 2x + \frac{(d_1 + d_2)^2}{4x}$

Show Answer

Answer: ((a))

$\frac{\pi}{2}(d_1 - d_2) + 2x + \frac{(d_1 + d_2)^2}{4x}$

Calculate the belt speed that results in maximum power, given a maximum tension of 2500 N and a belt mass of 0.9 kg/m.

((a))
21.4 m/s
((b))
22.5 m/s
((c))
30.4 m/s
((d))
20.4 m/s

Show Answer

Answer: ((a))

21.4 m/s

In a vapor absorption refrigeration system, the function of the absorber is to____.

((a))
Vaporize the refrigerant
((b))
Separate refrigerant from absorbent
((c))
Absorb refrigerant vapor into the absorbent
((d))
Increase refrigerant pressure

Show Answer

Answer: ((a))

Vaporize the refrigerant

In a simple vapour compression cycle, the throttling process is assumed to be_______.

((a))
isothermal
((b))
isentropic
((c))
isochoric
((d))
isenthalpic

Show Answer

Answer: ((a))

isothermal

An ideal Otto cycle has a compression ratio of 9. The specific heat ratio is 1.4. The approximate air-standard efficiency is _________.

((a))
56.7%
((b))
58.5%
((c))
61.4%
((d))
65.2%

Show Answer

Answer: ((a))

56.7%

A steam power plant operates on an ideal regenerative Rankine cycle. Steam enters the turbine at 40 bar and $400^{\circ}C$ . A fraction of steam is bled at 10 bar for regenerative feedwater heating. The condenser pressure is 0.8 bar. Pump work is neglected. What is the thermal efficiency of the cycle?

((a))
21.9%
((b))
25.3%
((c))
29.6%
((d))
36.4%

Show Answer

Answer: ((a))

21.9%

A reversible heat engine converts one-sixth of the supplied heat into work. When the sink temperature is lowered to 70°C, the thermal efficiency becomes twice its original value. Determine the temperatures of the source and the sink.

((a))
420K and 350K
((b))
350K and 300K
((c))
490K and 300K
((d))
490K and 350K

Show Answer

Answer: ((a))

420K and 350K

An air-standard Otto cycle has a thermal efficiency of 60%. The ratio of specific heats for the working fluid is $\gamma = 1.5$ . Determine the compression ratio of the engine.

((a))
6.25
((b))
4.41
((c))
8.50
((d))
5.25

Show Answer

Answer: ((a))

6.25

In a practical vapor compression refrigeration system, replacing a throttle valve with an isentropic expander will result in_______.

((a))
no change in performance
((b))
lower COP due to higher work requirement
((c))
same COP but higher refrigeration effect
((d))
higher COP due to work recovery

Show Answer

Answer: ((a))

no change in performance

A vapor compression refrigeration system uses Freon-12 as the refrigerant. The evaporator operates at $-10^{\circ}C$ and the condenser at $40^{\circ}C$ . The system provides a cooling capacity of 150W. Given that the enthalpy of saturated vapor at $-10^{\circ}C$ is $183kJ/kg$ and the enthalpy of saturated liquid at $40^{\circ}C$ is $74.5kJ/kg$ , determine the mass flow rate of the refrigerant.

((a))
0.00098 kg/s
((b))
0.00138 kg/s
((c))
0.00215 kg/s
((d))
0.00360 kg/s

Show Answer

Answer: ((a))

0.00098 kg/s

An ideal vapor compression refrigeration system operates with refrigerant R - 12. The refrigerant enters the compressor as dry saturated vapor at $-15^{\circ}C$ and leaves the condenser as saturated liquid at $30^{\circ}C$ . Compression is isentropic. Given that the enthalpy of dry saturated vapor at $-15^{\circ}C$ is 344.93 kJ/kg, the enthalpy of saturated liquid at $30^{\circ}C$ is 228.54 kJ/kg, and the compressor exit enthalpy is 369.68 kJ/kg, determine the coefficient of performance (COP) of the system.

((a))
3.25
((b))
5.80
((c))
6.95
((d))
4.70

Show Answer

Answer: ((a))

3.25

A rectangular plane surface, 2.5m wide and 4 m deep, is immersed in water such that its plane makes an angle of $40^{\circ}$ with the free surface. The upper edge of the plane surface is 2m below the free surface. Determine the position of the center of pressure, given that the density of the fluid is $1000kg/m^{3}$ .

((a))
3.45m below the free surface
((b))
2.45m below the free surface
((c))
1.45m below the free surface
((d))
2m below the free surface

Show Answer

Answer: ((a))

3.45m below the free surface

A plate is 0.04 mm away from a fixed plate and moves with a velocity of 0.8 m/s. The force required to maintain this speed is 3 N per $m^{2}$ . Find the viscosity of the fluid between the plates in $N\ sec/m^{2}$ ?

((a))
0.00030
((b))
0.00015
((c))
0.00045
((d))
0.00060

Show Answer

Answer: ((a))

0.00030

Find the surface tension in a soap bubble of 50 mm diameter when the inside pressure is $3\ N/m^{2}$ above atmospheric pressure.

((a))
0.01675 N/m
((b))
0.0175 N/m
((c))
0.01875 N/m
((d))
0.01775 N/m

Show Answer

Answer: ((a))

0.01675 N/m

The dynamic viscosity of an oil used for lubrication between a shaft and sleeve is 4 poise.

The shaft diameter is 0.3m, and it rotates at 240 rpm.

Calculate the power lost in the bearing if the sleeve length is 120 mm and the thickness of the oil film is 1 mm.

((a))
643.4 watt
((b))
700 watt
((c))
543.4 watt
((d))
1000 watt

Show Answer

Answer: ((a))

643.4 watt

Two soap bubbles of diameters 40 mm and 60 mm coalesce to form a single bubble.

Find the excess pressure inside the new bubble if the surface tension is 0.03 N/m.

((a))
0.67 $N/m^{2}$
((b))
1.67 $N/m^{2}$
((c))
4.67 $N/m^{2}$
((d))
3.67 $N/m^{2}$

Show Answer

Answer: ((a))

0.67 $N/m^{2}$

What is the effect on the internal excess pressure if the diameter of a soap bubble is doubled?

((a))
Double
((b))
Become half
((c))
Become one-fourth
((d))
Remain unchanged

Show Answer

Answer: ((a))

Double

If for a capillary tube the rise of water is 2 cm at $\theta=30^\circ$ , what will be the change in height if the contact angle changes to $\theta=45^\circ$ ? Assume other factors remain constant.

((a))
Height increases to about 2.41 cm
((b))
Height decreases to about 1.63 cm
((c))
Height decreases to about 1.414 cm
((d))
Height remains the same

Show Answer

Answer: ((a))

Height increases to about 2.41 cm

Under which condition will the body float in a stable equilibrium position?

Let: G- Centre of gravity, M- Metacentric height, B- Center of buoyancy

((a))
G is above M
((b))
M is above G
((c))
B is above G
((d))
G, B and M coincide

Show Answer

Answer: ((a))

G is above M

A body floating at the interface of two liquids will always have:

((a))
Equal volume in both liquids
((b))
Equal buoyant force from both liquids
((c))
Total buoyant force equal to weight
((d))
Higher density than both liquids

Show Answer

Answer: ((a))

Equal volume in both liquids

Which of the following statements best explains why work developed per kg of air is higher in a gas turbine than in an I.C. engine?

((a))
Higher compression ratio in gas turbines
((b))
Higher mechanical efficiency of gas turbines
((c))
Use of excess air for combustion in gas turbines
((d))
Expansion of gases up to atmospheric pressure in gas turbines

Show Answer

Answer: ((a))

Higher compression ratio in gas turbines

Who originally theorized the four-stroke cycle used in today's gasoline engines (Otto cycle)?

((a))
Rudolf Diesel
((b))
Bea de Rochas
((c))
Dugald Clerk
((d))
Nicolaus August Otto

Show Answer

Answer: ((a))

Rudolf Diesel

Which component is found in both gasoline (petrol) and diesel engines among these options?

((a))
Carburettor
((b))
Spark plug
((c))
Injector
((d))
Crankshaft

Show Answer

Answer: ((a))

Carburettor

In a four-stroke spark ignition engine, ignition of the fuel-air mixture occurs______.

((a))
during the suction stroke
((b))
at the beginning of compression stroke
((c))
during the exhaust stroke
((d))
near the end of the compression stroke

Show Answer

Answer: ((a))

during the suction stroke

A Pelton wheel is designed to develop 6000 kW under a net head of 300 m while running at 550 rpm. The overall efficiency is 85%, and the ratio of jet diameter to wheel diameter is $\frac{1}{10}$ . If the velocity coefficient Kv=0.98 and speed ratio Ku = 0.46, the number of jets required is:

((a))
1
((b))
2
((c))
3
((d))
4

Show Answer

Answer: ((a))

The draft tube of a Kaplan turbine has an inlet diameter of 2.6 m, and its inlet is 2.9 m above the tail race. The turbine develops 2100 metric horsepower under a net head of 6.5 m. A vacuum gauge fitted at the inlet of the draft tube shows a negative head of 4 m. The turbine efficiency is 86%. Atmospheric pressure = 10.3 m of water.

<br>

Determine the draft tube efficiency.

((a))
56%
((b))
66%
((c))
76%
((d))
86%

Show Answer

Answer: ((a))

56%

A Francis turbine is supplied through a 6 m diameter penstock and has the following data: Output = 63, 500 kW, Discharge = $117 m^3/s$ , Speed = 150 rpm, Hydraulic efficiency = 92%, Static pressure head at penstock just before runner = 57.4 m, velocity in tail race = 2.4 m/s, The pressure tap is 3 m above tail race. The net head acting on the turbine and the overall efficiency are approximately:

((a))
H = 55 m, $\eta_0 = 0.85$
((b))
H = 60.98 m, $\eta_0 = 0.907$
((c))
H = 65 m, $\eta_0 = 0.92$
((d))
H = 58 m, $\eta_0 = 0.88$

Show Answer

Answer: ((a))

H = 55 m, $\eta_0 = 0.85$

Steam enters a nozzle at a pressure of 10 bar with a specific volume of $0.25 m^3/kg$ . The index of expansion is n = 1.3, and the throat area is $0.01 m^2$ . Under isentropic conditions, determine the maximum possible steam mass flow rate.

((a))
13.5 kg/s
((b))
24.4 kg/s
((c))
4.6 kg/s
((d))
55.9 kg/s

Show Answer

Answer: ((a))

13.5 kg/s

A 13, 240 kW Francis turbine runs at 150 rpm under a net head of 27 m. The effective atmospheric pressure head is 10.6 m of water. The draft tube must extend at least 0.77 m below the tail race. The maximum permissible height of a straight conical draft tube is approximately:

((a))
1, 45 m
((b))
2.01 m
((c))
2.22 m
((d))
2.82 m

Show Answer

Answer: ((a))

1, 45 m

Steam expands isentropically through a nozzle with an adiabatic heat drop of 100 kJ/kg. Calculate the exit velocity of steam (assuming negligible inlet velocity).

((a))
320 m/s
((b))
447 m/s
((c))
520 m/s
((d))
400 m/s

Show Answer

Answer: ((a))

320 m/s

A cylinder of diameter 1.2 m rotates in the air, moving at 128 km/h. A lift of 5886 N per metre length is developed on the cylinder. Assuming ideal fluid theory, $\rho = 1.236 kg/m^3$ . Find the rotational speed of the cylinder in rpm and the location of the stagnation points.

((a))
N = 566 rpm; $\theta = -30^\circ$ and $210^\circ$
((b))
N = 500 rpm; $\theta = -45^\circ$ and $225^\circ$
((c))
N = 600 rpm; θ = -25^∘and 205^∘
((d))
N = 550 rpm; θ = -35^∘ and 215^∘

Show Answer

Answer: ((a))

N = 566 rpm; $\theta = -30^\circ$ and $210^\circ$

A kite weighing 12.26 N has an effective area of $0.9 m^2$ . The tension in the string is 32.37 N, and the string makes an angle of $45^\circ$ with the horizontal. The wind speed is 32 km/h. If the density of air is $1.203 kg/m^3$ , find the coefficients of drag CD and lift CL.

((a))
CD = 0.32, CL=0.58
((b))
CD = 0.45, CL = 0.71
((c))
CD = 0.535, CL = 0.822
((d))
CD = 0.72, CL = 0.41

Show Answer

Answer: ((a))

CD = 0.32, CL=0.58

In an impulse steam turbine, Adiabatic power, Rim power, and Shaft power are defined as $\dot{m}_s(h_1 - h_2)$ , $\dot{m}_s(h_1 - h_4)$ , and $\dot{m}_s(h_1 - h_5)$ ,respectively. The enthalpy $h_2$ accounts for losses in the nozzle, $h_4$ includes the effects of blade friction and windage losses, and $h_5$ further incorporates mechanical losses in power transmission. Based on these definitions and the nature of losses occurring at different stages of energy conversion in the turbine, which of the following statements correctly represents the relationship among Adiabatic power, Rim power, and Shaft power?

((a))
Rim power is greater than adiabatic power due to reheating in the blades
((b))
Shaft power is always equal to rim power
((c))
Net efficiency is independent of mechanical losses
((d))
Internal efficiency is based on the ratio of rim power to adiabatic power

Show Answer

Answer: ((a))

Rim power is greater than adiabatic power due to reheating in the blades

A centrifugal pump has an impeller of diameter 0.29 m running at 960 r.p.m. with an outlet vane angle of 28°. The velocity of flow is 2 m/s. The static suction lift is 2.8 m. Head losses are: suction pipe = 0.61 m, impeller = 0.49 m, volute casing = 0.88 m.

Find the pressure head readings at:

(i) Inlet to the pump

(ii) Impeller outlet

((a))
Inlet = -2.8 m, Impeller outlet = 7 m
((b))
Inlet = -3.6 m, Impeller outlet = 12 m
((c))
Inlet = -4.2 m, Impeller outlet = 18 m
((d))
Inlet = -3.1 m, Impeller outlet = 24 m

Show Answer

Answer: ((a))

Inlet = -2.8 m, Impeller outlet = 7 m

Consider an ideal Diesel cycle under cold air-standard assumptions ( $k = 1.4$ ), with compression ratio $r = 18$ and cut-off ratio $\alpha = 2$ . The thermal efficiency is closest to ___.

((a))
48%
((b))
72%
((c))
55%
((d))
63%

Show Answer

Answer: ((a))

48%

Identify the correct sequence of thermodynamic processes in an ideal Brayton cycle used in gas turbines.

((a))
Isothermal compression, constant-volume heat addition, isothermal expansion, constant-pressure heat rejection
((b))
Isentropic compression, constant-pressure heat addition, isentropic expansion, constant-pressure heat rejection
((c))
Constant-pressure compression, isentropic heat addition, constant-volume expansion, isentropic heat rejection
((d))
Isentropic compression, constant-volume heat addition, isothermal expansion, constant-pressure heat rejection

Show Answer

Answer: ((a))

Isothermal compression, constant-volume heat addition, isothermal expansion, constant-pressure heat rejection

In a pumping station, $18,000m^3$ of water per day is to be pumped from an intake well to a sedimentation tank under a static head of 21 m. The suction pipe length is 40 m, and the rising main length is 150 m. The diameter of both pipes is 0.5 m. The pumps operate in two 8-hour shifts. The coefficient of friction is 0.01, and the combined efficiency of motor and pump is 80%. Each pump has a capacity of 30 BHP.

Determine the number of pumps required.

((a))
2
((b))
3
((c))
4
((d))
5

Show Answer

Answer: ((a))

A Pelton wheel having semi-circular buckets works under a head of 140 m. It runs at 600 r.p.m. The discharge through the nozzle is 500 L/s, and the wheel diameter is 0.6m. The coefficient of velocity of the jet is 0.98.

Find:

(a) Power available at the nozzle

(b) Hydraulic efficiency of the wheel

((a))
Power = 686.7 kW, $\eta_h$ = 92.9%
((b))
Power = 612.5 kW, $\eta_h$ = 85.0%
((c))
Power = 735.0 kW, $\eta_h$ = 90.2%
((d))
Power = 686.7 kW, $\eta_h$ = 88.5%

Show Answer

Answer: ((a))

Power = 686.7 kW, $\eta_h$ = 92.9%

Which of the following combinations of reasons best explains the widespread engineering use of ferrous alloys?

((a))
Abundant iron compounds, economical processing, and a wide property range
((b))
High melting point, ease of welding, and magnetic behaviour
((c))
Low-cost, alloying elements, corrosion resistance and hardness
((d))
Ease of recycling, low density, and thermal stability

Show Answer

Answer: ((a))

Abundant iron compounds, economical processing, and a wide property range

Which microstructural constituents are explicitly stated to dominate low-carbon steels in their normal condition?

((a))
Austenite and bainite
((b))
Martensite and ferrite
((c))
Cementite and martensite
((d))
Ferrite and pearlite

Show Answer

Answer: ((a))

Austenite and bainite

Why are plain medium carbon steels difficult to heat treat successfully in thick sections?

((a))
They possess low hardenability requiring rapid quenching
((b))
They transform completely to ferrite during cooling
((c))
They form excessive retained austenite
((d))
Alloy carbides prevent martensite formation

Show Answer

Answer: ((a))

They possess low hardenability requiring rapid quenching

In the AISI SAE steel designation system, what do the last two digits of a four-digit steel number represent?

((a))
Manganese concentration multiplied by 100
((b))
Carbon concentration multiplied by 100
((c))
Carbon concentration multiplied by 1000
((d))
Manganese concentration multiplied by 1000

Show Answer

Answer: ((a))

Manganese concentration multiplied by 100

Why can two steel alloys with identical carbon content exhibit identical hardness at the quenched end but significantly different hardness profiles inward?

((a))
Carbon content controls both surface and interior hardness
((b))
Quenching medium alters martensite hardness
((c))
Grain size variation dominates hardness near the surface
((d))
Alloying elements delay diffusional transformations during cooling

Show Answer

Answer: ((a))

Carbon content controls both surface and interior hardness

During arc welding of steel, the welding voltage is 25V , and the current is 160A. The welding speed is 4 mm per second, and the cross-sectional area of the weld joint is $15mm^2$ . The heat required to melt steel is 9J per $mm^3$ and the heat transfer efficiency is 0.8. What is the melting efficiency of the welding process?

((a))
0.12
((b))
0.17
((c))
0.25
((d))
0.54

Show Answer

Answer: ((a))

0.12

Which expression correctly represents the net free energy change for the formation of a spherical solid nucleus of radius R during nucleation from a melt according to the free energy concept?

((a))
$\Delta f = -(\frac{4}{3})\pi R^3 \Delta F + 4\pi R^2 \sigma$
((b))
$\Delta f = -4\pi R^3 \Delta F + \left(\frac{4}{3}\right)\pi R^2 \sigma$
((c))
$\Delta f = \left(\frac{4}{3}\right)\pi R^3 \Delta F - 4\pi R^2 \sigma$
((d))
$Δf=( 3 4 )πR 3 ΔF+4πR 2 σ$

Show Answer

Answer: ((a))

$\Delta f = -(\frac{4}{3})\pi R^3 \Delta F + 4\pi R^2 \sigma$

In direct extrusion, the extrusion pressure p depends on the yield strength of the billet material Y, the billet diameter Db, and the extruded product diameter De. Which of the following expressions correctly gives the extrusion pressure p?

((a))
$p = Y [1.7 + \ln(Db/De)^2]$
((b))
$p = Y \ln[1 + 1.7(Db/De)]$
((c))
$p = Y [1 + \ln(De/Db)]$
((d))
$p = Y [1 + 1.7\ln(Db/De)]$

Show Answer

Answer: ((a))

$p = Y [1.7 + \ln(Db/De)^2]$

Identify the option listing exclusively defects originating from the metal rolling operation.

((a))
Laps, scale rolled-in, scabs, seams
((b))
Gas blowholes, laps, scabs, seams
((c))
Cold shuts, rolled-in scale, porosity, laps
((d))
Hot tears, slivers, blowholes, shrinkage voids

Show Answer

Answer: ((a))

Laps, scale rolled-in, scabs, seams

Which of the following combinations of statements about hot extrusion processes is completely correct?

Statements:

In forward hot extrusion, metal flows in the same direction as the ram movement and friction exists between the billet and the container wall.
In backward hot extrusion, metal flows opposite to the ram movement and billet-container friction is essentially eliminated because the billet remains stationary relative to the container.
In backward hot extrusion, extrusion pressure increases with billet length due to increased friction at the container wall.
In hot extrusion of steels, molten glass is used as a lubricant and as a thermal insulator at high temperatures.

((a))
1, 2 and 4only
((b))
1, 3 only
((c))
2 and 3 only
((d))
1, 3 and 4 only

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Answer: ((a))

1, 2 and 4only

A gas mass undergoes quasi-static compression from 100 kPa, 0.12 $m^3$ to 500 kPa, 0.04 $m^3$ . Assuming that the pressure and volume are related by $PV^n = C$ .

Calculate the work done by the gas (in kJ).

((a))
100 kJ
((b))
15 kJ
((c))
-10 kJ
((d))
-17.2 kJ

Show Answer

Answer: ((a))

100 kJ

2 moles of ideal gas ( $\gamma$ =1.33) undergo adiabatic compression, with temperature rising from $300^\circ C$ to $420^\circ C$ .

Calculate the change in internal energy (kJ).

((a))
1.0 kJ
((b))
10 kJ
((c))
4.5 kJ
((d))
6.05 kJ

Show Answer

Answer: ((a))

1.0 kJ

A heat engine drives a heat pump. The engine's rejected heat plus the pump's delivered heat both warm circulating water in building radiators. Engine efficiency is 30%; heat pump COP is 3.5.

Find the ratio of total heat to water divided by heat input to the engine.

((a))
2
((b))
1.75
((c))
1.5
((d))
3.75

Show Answer

Answer: ((a))

A heat engine absorbs 1000 kW at a constant 285°C and rejects 492 kW of heat at 5°C.

Consider the following thermodynamic cycles in this regard:

Carnot cycle
Reversible cycle
Irreversible cycle

Which could this engine represent?

((a))
1 only
((b))
2 only
((c))
1 and 2 only
((d))
None of 1, 2 and 3

Show Answer

Answer: ((a))

1 only

A wet steam mixture has a specific liquid volume of : $V_f = 0.0012 m^3/kg$ and vapour specific volume, $V_g = 1.25 m^3/kg$ .

With a dryness fraction of x = 0.08, calculate the vapour's volume fraction in the mixture.

((a))
0.921
((b))
0.988
((c))
0.888
((d))
0.50

Show Answer

Answer: ((a))

0.921

A rigid steel tank contains a liquid-vapour mixture of ammonia at 25°C. The total volume of the tank is $0.012 m^3$ . The critical specific volume of ammonia is: $V_c = 0.0043 m^3/kg$ .

The tank is heated slowly at constant volume.

Case 1: Total mass = 4 kg

Case 2: Total mass = 0.8 kg

What will happen to the liquid level inside the tank during heating?

((a))
In both cases liquid level will decrease
((b))
In both cases liquid level will increase
((c))
For case 1 liquid level will rise and for case 2 liquid level will decrease
((d))
For case 1 liquid level decrease and for case 2 liquid level increase

Show Answer

Answer: ((a))

In both cases liquid level will decrease

A closed system containing an ideal gas undergoes a process from state 1 to state 2 along two different paths. Along path A, the system receives 500 kJ of heat and does 300 kJ of work. Along path B, it receives 700 kJ of heat and does 500 kJ of work. The initial and final states are identical in both cases. Which of the following statements is CORRECT?

((a))
Internal energy change is different for the two paths
((b))
Heat and work are point functions
((c))
Internal energy change is the same for both paths
((d))
Entropy change must be zero for both paths

Show Answer

Answer: ((a))

Internal energy change is different for the two paths

A cyclic heat engine operates between two thermal reservoirs. During one complete cycle, the net work output is positive, and the internal energy of the working fluid remains unchanged.

Which of the following cannot be determined using the First Law alone?

((a))
Net heat supplied to the engine
((b))
Net work output of the engine
((c))
Whether the engine violates thermodynamic laws
((d))
Energy balance over the cycle

Show Answer

Answer: ((a))

Net heat supplied to the engine

A closed system undergoes an adiabatic expansion process with significant frictional effects inside the system. No heat interaction occurs with the surroundings.

Which of the following statements is TRUE?

((a))
Entropy of the system remains constant
((b))
Entropy of the system decreases
((c))
Entropy of the system increases
((d))
Process must be isentropic

Show Answer

Answer: ((a))

Entropy of the system remains constant

A rigid body experiences a force F at point A, producing specific external effects. The same force F is then applied at point B along the identical line of action, where B is closer to the center of mass than A. For a perfectly rigid body, considering only external effects, which statement is MOST CORRECT?

((a))
The external effect remains unchanged, but internal stresses definitely change.
((b))
The external effect changes because the moment arm with respect to the center of mass changes.
((c))
Both external effect and internal stresses remain unchanged.
((d))
The external effect remains unchanged only if the body is in equilibrium.

Show Answer

Answer: ((a))

The external effect remains unchanged, but internal stresses definitely change.

A rigid body initially at rest is acted upon by a single force F. An additional force system is then applied such that its net force and net moment are both zero. Simultaneously, the original force F is shifted along its line of action to a new point on the body. Which conclusion is correct?

((a))
The body will accelerate due to the redistribution of forces.
((b))
The external effect on the body remains unchanged, but the internal force distribution may change.
((c))
The equilibrium of the body is disturbed due to shifting of force.
((d))
The body will rotate because the point of application has changed.

Show Answer

Answer: ((a))

The body will accelerate due to the redistribution of forces.

Two forces, P and Q, act simultaneously at a point on a body, with an angle $\theta$ between them. Their resultant is found using the parallelogram law of forces. Consider also a gravitational system where two masses attract each other with equal-magnitude, opposite-direction forces. Which statement best explains the common fundamental principle behind both situations?

((a))
Both rely on Newton’s third law only.
((b))
Both demonstrate that forces are independent of their points of application.
((c))
Both show that forces are vector quantities and combine according to vector addition laws.
((d))
Both prove that resultant force always acts along the line joining the centers of masses.

Show Answer

Answer: ((a))

Both rely on Newton’s third law only.

Two forces of magnitudes P=40 N and Q=60 N act at a point, making an angle of 60°between them. Using the

parallelogram law, the resultant force (in N) and angle with force P (in degrees) are:

((a))
87.18, 36.6°
((b))
67.18, 32.6°
((c))
87.18, 26.6°
((d))
75.18, 36.6°

Show Answer

Answer: ((a))

87.18, 36.6°

Three forces P, Q, and R keep a particle in equilibrium. The angles between them are: between Q and R = 90°, between P and R = 60°, between P and Q = 210°. If Q = 100 N, find P and R.

((a))
115.47 N, -57.74 N
((b))
-115.47 N, 57.4 N
((c))
120 N , 25 N
((d))
115.7 N, -47.4 N

Show Answer

Answer: ((a))

115.47 N, -57.74 N

Varignon's principle of moments states that the moment of the resultant force about any point equals:

((a))
The moment of the largest force about that point.
((b))
The sum of moments of only the parallel forces about that point.
((c))
The algebraic sum of the moments of all the component forces about the same point.
((d))
The product of the resultant force and the distance of its point of application point.

Show Answer

Answer: ((a))

The moment of the largest force about that point.

A rectangle of width b and depth d has its base on the x-axis. The moment of inertia about the base is:

((a))
$\frac{bd^3}{12}$
((b))
$\frac{bd^3}{6}$
((c))
$\frac{bd^3}{3}$
((d))
$\frac{bd^3}{24}$

Show Answer

Answer: ((a))

$\frac{bd^3}{12}$

For a triangular lamina of base b and height h, the ratio of the moment of inertia about its base to that about its centroidal axis parallel to the base is:

((a))
2 : 1
((b))
4 : 1
((c))
6 : 1
((d))
3 : 1

Show Answer

Answer: ((a))

2 : 1

A block of mass m is placed on a rough horizontal surface. A force F is applied on the block at an angle $\theta$ above the horizontal. The coefficient of kinetic friction between the block and surface is $\mu_k$ .

Assuming the block moves towards the right, the acceleration of the block is (g = acceleration due to gravity):

((a))
a= F/m cos $\theta$ - $\mu_k$ (g-F/m sin $\theta$ )
((b))
a= F/m cos $\theta$ + $\mu_k$ (g-F/m sin $\theta$ )
((c))
a= F/m sin $\theta$ - $\mu_k$ (g-F/m cos $\theta$ )
((d))
a= F/m cos $\theta$ - $\mu_k$ (g+F/m sin $\theta$ )

Show Answer

Answer: ((a))

a= F/m cos $\theta$ - $\mu_k$ (g-F/m sin $\theta$ )

In a Whitworth quick return mechanism, the fixed link measures 120 mm while the crank radius is 300 mm. Calculate the cutting stroke to return stroke time ratio.

((a))
1.35
((b))
1.71
((c))
1.52
((d))
1.85

Show Answer

Answer: ((a))

1.35

Two parallel shafts offset by 80 mm are joined by an Oldham coupling. At a 900 rpm driving speed, find the maximum sliding velocity of the intermediate disc.

((a))
6.54 m/sec
((b))
8.54 m/sec
((c))
7.54 m/sec
((d))
9.42 m/sec

Show Answer

Answer: ((a))

6.54 m/sec

An Oldham coupling joins two parallel shafts offset by 50 mm, with an intermediate disc maximum sliding velocity of 10 m/s. Find the driving shaft speed.

((a))
1710 RPM
((b))
1820 RPM
((c))
1910 RPM
((d))
2000 RPM

Show Answer

Answer: ((a))

1710 RPM

A rack-pinion has a pinion with 24 involute teeth, 144 mm pitch circle diameter, the addendum of the pinion as well as the addendum of the rack is 6 mm, and $20^\circ$ pressure angle. Calculate the contact ratio of the rack and pinion mechanism.

((a))
1
((b))
5.72
((c))
2.72
((d))
1.72

Show Answer

Answer: ((a))

In the differential gear of a car, the pinion mounted on the propeller shaft has 20 teeth and the crown gear has 100 teeth. The propeller shaft rotates at 600 rpm. When the vehicle is taking a turn, one wheel rotates at 140 rpm. Determine the percentage change in speed of the other wheel.

((a))
10.52%
((b))
16.67%
((c))
20%
((d))
11.67%

Show Answer

Answer: ((a))

10.52%

In a four-stroke engine, the turning moment diagram is represented by four triangles with the following areas:

· Expansion = 8.0 $cm^2$

· Compression = 2.2 $cm^2$ (-ve)

· Suction = 0.6 $cm^2$ (-ve)

· Exhaust = 0.8 $cm^2$ (-ve)

<br>

If 1 $cm^2$ = 1200J, find the mean torque developed by the engine.

((a))
420.3 N-m
((b))
535.5 N-m
((c))
612.4 N-m
((d))
380.2 N-m

Show Answer

Answer: ((a))

420.3 N-m

Which condition must hold for a four-bar mechanism to function as a crank-rocker mechanism?

((a))
The longest link is fixed
((b))
The shortest link is fixed
((c))
A link adjacent to the shortest link is fixed
((d))
Any link can be fixed

Show Answer

Answer: ((a))

The longest link is fixed

In a planar four-bar mechanism where $s + l = p + q$ (s = shortest link, l = longest link, p and q = the other links), which statement is NOT true about the inversions when fixing different links?

((a))
Fixing the shortest link always produces a double-crank mechanism
((b))
Fixing a link adjacent to the shortest link results in a crank-rocker mechanism
((c))
Fixing the link opposite to the shortest link produces a double-rocker mechanism
((d))
No inversion will permit full rotation of any link

Show Answer

Answer: ((a))

Fixing the shortest link always produces a double-crank mechanism

A single slider-crank chain yields four distinct inversions depending on which link is fixed as the frame. Which statement accurately identifies the application of one such inversion?

((a))
Fixing the crank produces a quick return mechanism
((b))
Fixing the connecting rod results in a mechanism used in hand pumps
((c))
Fixing the slider gives an oscillating cylinder engine mechanism
((d))
Fixing the frame produces the Whitworth quick return mechanism

Show Answer

Answer: ((a))

Fixing the crank produces a quick return mechanism

Identify the lathe type characterized by high RPM range (1200-3600), no power feed mechanism, and primary use in polishing/metal spinning operations:

((a))
Engine lathe
((b))
Bench lathe
((c))
Tool room lathe
((d))
Speed lathe

Show Answer

Answer: ((a))

Engine lathe

A lathe suited for producing gauges, dies, and jigs while demanding superior dimensional precision should ideally be:

((a))
Bench lathe
((b))
Tool room lathe
((c))
Capstan lathe
((d))
Automatic lathe

Show Answer

Answer: ((a))

Bench lathe

Which machining operation best achieves $Ra = 0.4 \mu m$ surface finish per standard roughness range?

((a))
Boring
((b))
Milling
((c))
Planning
((d))
Sawing

Show Answer

Answer: ((a))

Boring

For tempering cutting tools like shear blades and milling cutters under heavy loads and wear, which oxide color-temperature pair offers the best balance of hardness and toughness?

((a))
Straw colour - 230°C
((b))
Dark straw - 225°C
((c))
Pale blue - 280°C
((d))
Golden yellow - 240°C

Show Answer

Answer: ((a))

Straw colour - 230°C

While turning a taper using a taper turning attachment set to 4°, the cutting tool is positioned 3mm below the centre. With a small end diameter of 40mm and a taper length of 100mm, what actual taper angle results?

((a))
4.000°
((b))
4.0303°
((c))
3.9697°
((d))
3.8000°

Show Answer

Answer: ((a))

4.000°

In orthogonal cutting on steel with a 10° rake tool: depth of cut = 2mm , feed = 0.20 mm/rev, cutting speed = 200m/min , chip thickness ratio r = 0.31 , vertical cutting force Fv = 1200N, horizontal cutting force F_h = 650N. Using Merchant's theory, calculate the shear stress on the shear plane.

((a))
145 MPa
((b))
168 MPa
((c))
192 MPa
((d))
225 MPa

Show Answer

Answer: ((a))

145 MPa

In an orthogonal cutting test using a tool of 10° rake angle: chip thickness ratio r = 0.3, horizontal cutting force F_H = 1290 N, vertical cutting force F_V = 1650 N. Using Merchant's theory, determine the coefficient of friction at

the chip-tool interface.

((a))
2.25
((b))
1.88
((c))
1.53
((d))
1.21

Show Answer

Answer: ((a))

2.25

A 40 mm diameter, 50 mm deep hole is drilled in a mild steel plate. Cutting speed = 65 m/min, feed = 0.25 mm/rev. Determine the approximate machining time and material removal rate (MRR).

((a))
Time = 0.38 min, MRR = 162 cm³ /min
((b))
Time = 0.25 min, MRR = 100 cm³ /min
((c))
Time = 0.50 min, MRR = 200 cm³ /min
((d))
Time = 0.15 min, MRR = 80 cm³ /min

Show Answer

Answer: ((a))

Time = 0.38 min, MRR = 162 cm³ /min

100

A 6m × 1.25m grey cast iron plate is machined on a double housing planer using carbide tools. Cutting speed = 80m/min, return speed = 160m/min. Two roughing cuts at 1.5mm/strokefeed, two finishing cuts at 0.5mm/stroke. Table reversal time = 0.02min/stroke. The total machining time is closest to:

((a))
9.5 hours
((b))
11.2 hours
((c))
14.7 hours
((d))
18.3 hours

Show Answer

Answer: ((a))

9.5 hours

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