← MES Jr. Grade
Past Questions — 2024
The ductility of a material is to the increase in percentage reduction in an area.
A)
inversely proportional
B)
directly proportional
C)
equal
D)
uniform
Ductility is a mechanical property of a material that allows it to undergo significant plastic deformation under tensile stress before rupture. In material science, ductility is quantitatively measured using two primary parameters: 1) Percentage Elongation and 2) Percentage Reduction in Area. The 'Percentage Reduction in Area' is calculated as [(Original Area - Final Area) / Original Area] * 100. A material that is highly ductile will experience a significant 'necking' effect, leading to a large reduction in the cross-sectional area at the point of fracture. Therefore, as the ductility of a material increases, the percentage reduction in area also increases. This positive correlation means that ductility is directly proportional to the increase in percentage reduction in area.
To determine hoop stress, efficiency of is to be considered.
A)
Construction joint
B)
Transverse joint
C)
Longitudinal joint
D)
Rivetjoint
Hoop stress (also known as circumferential stress) occurs in cylindrical pressure vessels due to internal pressure. The stress acts along the circumference of the cylinder, which tends to pull the cylinder walls apart along its length. In a manufactured pressure vessel, the cylinder is typically formed from a flat plate rolled into a cylinder and joined along its length. This joint is called the 'longitudinal joint'. Because the hoop stress is the primary stress acting to pull this joint apart, the efficiency of the longitudinal joint (the ratio of the strength of the joint to the strength of the solid plate) must be considered to determine the safe working pressure or the actual stress the vessel can withstand. Transverse joints (circumferential joints) are subjected to longitudinal stress, which is only half the magnitude of the hoop stress, making the longitudinal joint the critical factor for hoop stress calculations.
The following is not a friction clutch
A)
Centrifugal clutch
B)
Cone clutch
C)
Disc clutch
D)
Fluid clutch
A friction clutch is a device that transmits torque from one shaft to another through the application of friction between two surfaces.
1. Centrifugal clutch (Option a): Uses centrifugal force to push friction pads against a drum to engage the drive. It is a friction clutch.
2. Cone clutch (Option b): Uses conical surfaces that press against each other to transmit torque via friction. It is a friction clutch.
3. Disc clutch (Option c): Uses flat friction plates (discs) pressed together to transmit torque. It is a friction clutch.
4. Fluid clutch (Option d): Also known as a fluid coupling, it transmits torque through the hydrodynamic action of a fluid (usually oil) between an impeller and a runner. There is no physical contact or sliding friction between the driving and driven members. Therefore, it is a hydraulic/fluid coupling, not a friction clutch.
A T-section beam is simply supported and subjected to a uniform distributed load over its whole span. Maximum longitudinal stress at
A)
Top fibre of the flange
B)
The junction of web and flange
C)
The mid-section of the web
D)
The bottom fibre of the web
1. **Bending Stress Formula**: The longitudinal stress (bending stress) in a beam is given by the formula σ = (M * y) / I, where M is the bending moment, y is the distance from the neutral axis (NA), and I is the moment of inertia.
2. **Neutral Axis Position**: In a T-section, the area is concentrated at the top (the flange). Consequently, the centroid (Neutral Axis) shifts upwards toward the flange.
3. **Distance 'y'**: The maximum stress occurs at the fiber furthest from the neutral axis. Because the NA is shifted upwards, the distance from the NA to the bottom fiber of the web (y_bottom) is significantly greater than the distance from the NA to the top fiber of the flange (y_top).
4. **Comparison**: Since σ is directly proportional to y, and y_bottom > y_top, the maximum longitudinal stress will occur at the bottom-most fiber of the beam.
5. **Conclusion**: For a simply supported beam under UDL, the maximum bending moment occurs at the center, and the maximum stress at that section occurs at the fiber furthest from the NA, which is the bottom fiber of the web.
During tensile-testing of a specimen using a Universal Testing Machine, the parameters actually measured include
A)
True stress and true strain
B)
Poisson’s ratio and Young’s modulus
C)
Engineering stress and engineering strain
D)
Load and elongation
In a tensile test conducted using a Universal Testing Machine (UTM), the machine is equipped with sensors (such as a load cell for force and an extensometer or crosshead displacement sensor for length change). Therefore, the raw data 'actually measured' by the hardware are the applied Load (P) and the resulting Elongation (ΔL).
All other parameters mentioned in the options are 'calculated' or 'derived' values:
- Engineering Stress (σ = P/A₀) and Engineering Strain (ε = ΔL/L₀) are calculated by dividing the measured load and elongation by the original cross-sectional area and original length, respectively.
- True Stress and True Strain are derived from engineering values by accounting for the instantaneous change in area and length during deformation.
- Young's Modulus (E = σ/ε) and Poisson's ratio are material properties calculated from the slope of the stress-strain curve and the ratio of lateral to longitudinal strain, respectively.
Since the question asks for parameters 'actually measured', the correct answer is Load and elongation.
A weight falls on a plunger fitted in a container filled with oil thereby producing a pressure of 1.5 N/mm² in the oil. The Bulk Modulus of oil is 2800 N/mm². Given this situation, the volumetric compressive strain produced in the oil will be:
A)
400 x 10⁻⁶
B)
800 x 10⁻⁶
C)
268 x 10⁻⁶
D)
535 x 10⁻⁶
To find the volumetric compressive strain, we use the definition of the Bulk Modulus of elasticity.
1. **Given Data:**
- Pressure produced (Change in pressure, ΔP) = 1.5 N/mm²
- Bulk Modulus of oil (K) = 2800 N/mm²
2. **Formula:**
The Bulk Modulus (K) is defined as the ratio of the change in pressure (ΔP) to the volumetric strain (εᵥ):
K = ΔP / εᵥ
3. **Calculation:**
Rearranging the formula to solve for volumetric strain (εᵥ):
εᵥ = ΔP / K
εᵥ = 1.5 / 2800
εᵥ ≈ 0.000535714
4. **Converting to Scientific Notation:**
εᵥ = 535.714 x 10⁻⁶
Comparing this result to the given options, it aligns most closely with option (d) 535 x 10⁻⁶.
- Option (a) 400 x 10⁻⁶ is incorrect as it would require a pressure of ~1.12 N/mm².
- Option (b) 800 x 10⁻⁶ is incorrect as it would require a pressure of ~2.24 N/mm².
- Option (c) 268 x 10⁻⁶ is incorrect as it would require a pressure of ~0.75 N/mm².
A solid circular shaft of diameter 100 mm is subjected to an axial stress of 50 MPa. It is further subjected to a torque of 10 kNm. The maximum principal stress experienced on the shaft is closest to
A)
41 MPa
B)
82 MPa
C)
164 MPa
D)
204 MPa
Step-by-step solution:
1. **Given Data:**
- Diameter of shaft (d) = 100 mm = 0.1 m
- Axial stress (σₓ) = 50 MPa = 50 × 10⁶ N/m²
- Torque (T) = 10 kNm = 10 × 10³ Nm
2. **Calculate Torsional Shear Stress (τ):**
The shear stress induced by torque in a solid circular shaft is given by:
τ = (16T) / (πd³)
τ = (16 × 10,000) / (π × 0.1³)
τ = 160,000 / (π × 0.001)
τ = 160,000,000 / π ≈ 50.93 MPa
3. **Calculate Maximum Principal Stress (σ₁):**
The shaft is subjected to a combined state of axial stress (σₓ) and shear stress (τ). The formula for the maximum principal stress is:
σ₁ = (σₓ / 2) + √((σₓ / 2)² + τ²)
σ₁ = (50 / 2) + √((50 / 2)² + 50.93²)
σ₁ = 25 + √(25² + 50.93²)
σ₁ = 25 + √(625 + 2593.86)
σ₁ = 25 + √3218.86
σ₁ = 25 + 56.73
σ₁ = 81.73 MPa
4. **Conclusion:**
The calculated maximum principal stress is approximately 81.73 MPa, which is closest to 82 MPa.
Comparing with options:
- (a) 41 MPa: Incorrect.
- (b) 82 MPa: Correct (closest value).
- (c) 164 MPa: Incorrect.
- (d) 204 MPa: Incorrect.
Which of the following methods is also known as individual wall method?
A)
Centre line method
B)
Alignment method
C)
Long wall and short wall method
D)
Voluminous method
In civil engineering estimation and costing, there are two primary methods used for calculating the quantities of masonry and concrete work in buildings: the Centre Line Method and the Long Wall-Short Wall Method.
1. **Long Wall and Short Wall Method**: This method is also known as the **Individual Wall Method** or the Out-to-Out and In-to-In method. In this approach, the lengths of the long walls and short walls are calculated separately. The long walls are measured from the outer face to the outer face, and the short walls are measured between the inner faces of the long walls. This ensures that no volume is counted twice and each wall is treated as an individual entity.
2. **Centre Line Method**: This method involves calculating the total length of the center line of all walls and multiplying it by the width and height. Deductions are then made at junctions (T-junctions or cross-junctions) to avoid double counting. It is faster but not an 'individual wall' approach.
3. **Alignment and Voluminous methods**: These are not standard technical terms for calculating masonry quantities in building estimation.
Therefore, the Long Wall and Short Wall method is the correct answer as it treats walls individually.
The governor used in gramophone is of the following type
A)
Pickering
B)
Porter
C)
Hartnell
D)
Watt
A governor is a device used to maintain a constant speed of a machine regardless of the load. In the context of a gramophone (record player), it is critical to maintain a very precise and constant angular velocity to ensure the music plays at the correct pitch and tempo.
1. **Pickering Governor**: This is a centrifugal governor specifically designed for high precision and sensitivity in a compact space. It uses a spring-loaded mechanism that can react quickly to small changes in speed, making it ideal for the speed regulation required in gramophones.
2. **Porter Governor**: This is a dead-weight governor (a modification of the Watt governor) used primarily in large steam engines. It is too bulky and lacks the sensitivity required for a small electronic/mechanical device like a gramophone.
3. **Hartnell Governor**: This is a spring-loaded governor used in industrial applications where a wide range of speed control is needed. While it uses a spring, its design is intended for larger machinery rather than the precision instrumentation of a record player.
4. **Watt Governor**: This is the simplest form of a centrifugal governor (centrifugal balls on a rotating arm). It is highly inefficient at high speeds and lacks the precision needed for audio playback devices.
Therefore, the Pickering governor is the correct choice for the specific application of a gramophone.
Belt slip may occur due to
A)
Heavy load
B)
Loose belt
C)
Driving pulley too small
D)
All of these
Belt slip occurs when the frictional force between the belt and the pulley is insufficient to transmit the required torque. The condition for no-slip is governed by the belt tension ratio formula: (T1/T2) ≤ e^(μθ), where T1 is the tight side tension, T2 is the slack side tension, μ is the coefficient of friction, and θ is the angle of wrap.
1. Heavy load (Option a): An increase in load increases the required torque, which increases the difference between T1 and T2. If T1/T2 exceeds e^(μθ), the belt will slip.
2. Loose belt (Option b): A loose belt reduces the initial tension (T0), which directly lowers the normal force acting on the pulley surface. Since frictional force is proportional to the normal force (F = μN), a loose belt significantly reduces the grip, leading to slip.
3. Driving pulley too small (Option c): A smaller pulley diameter reduces the angle of wrap (θ) if the center distance remains constant, or it increases the bending stress and reduces the effective contact area/pressure distribution. A smaller θ decreases the value of e^(μθ), making the system more prone to slipping.
Since all three factors contribute to the occurrence of belt slip, the correct option is 'All of these'.
In a single slider four-bar linkage, when the slider is fixed, it forms a mechanism of
A)
hand pump
B)
reciprocating engine
C)
quick return
D)
oscillating cylinder
A single slider-crank mechanism consists of four links: a frame (fixed link), a crank, a connecting rod, and a slider. The inversion of a mechanism occurs when a different link is chosen as the fixed link.
1. **First Inversion (Frame fixed):** This is the standard reciprocating engine or compressor where the cylinder is fixed and the piston reciprocates. (Option b)
2. **Second Inversion (Crank fixed):** This results in a mechanism where the cylinder oscillates. Examples include the oscillating cylinder engine or the Whitworth quick return mechanism (though the quick return is a specific application of this inversion). (Option d)
3. **Third Inversion (Connecting rod fixed):** This results in a crank and slider both rotating, used in the hand pump (Option a) or the rotary engine.
In this specific question, the 'slider' is fixed. When the slider is fixed, the cylinder (which normally houses the slider) is forced to move/pivot relative to the other links. This creates the 'oscillating cylinder' mechanism. While 'quick return' mechanisms are derived from the second inversion (fixed crank), the most direct description of the physical arrangement when the slider is fixed is the oscillating cylinder mechanism.
Which of the following is a spring-controlled governor?
A)
Hartnell governor
B)
Hartung governor
C)
Wilson-Hartnell governor
D)
All of these
Governors are devices used to maintain the speed of an engine within specified limits regardless of the load. They are broadly classified into two types: Centrifugal Governors (which are further divided into Pendulum type and Fly-ball type) and Spring-controlled Governors.
1. Hartnell Governor: This is a classic example of a spring-loaded governor where a central spring provides the controlling force to counteract the centrifugal force of the rotating balls.
2. Hartung Governor: This is a specific type of spring-controlled governor where the spring is arranged such that the controlling force remains constant regardless of the lift of the sleeve.
3. Wilson-Hartnell Governor: This is a modification of the Hartnell governor that incorporates an additional spring to provide a more linear relationship between speed and lift, improving the sensitivity and stability of the governor.
Since all three listed governors (Hartnell, Hartung, and Wilson-Hartnell) utilize a spring to provide the controlling force, the correct option is 'All of these'.
A test specimen is stressed slightly beyond the yield point and then unloaded. Its yield strength will
A)
Decrease
B)
Increase
C)
Remains same
D)
Becomes equal to ultimate tensile strength
This phenomenon is known as 'Strain Hardening' or 'Work Hardening'. When a ductile material (like mild steel) is stressed beyond its yield point, it undergoes plastic deformation. During this process, dislocations within the crystal lattice of the metal multiply and tangle, creating barriers to further dislocation movement. When the specimen is unloaded and then re-loaded, the material exhibits a higher yield strength than it did originally. The new yield point is effectively the stress level at which the material was previously unloaded. Therefore, the yield strength increases.
- Option (a) is incorrect because the material becomes stronger (harder), not weaker.
- Option (c) is incorrect because the internal structure of the material has been permanently altered by plastic deformation.
- Option (d) is incorrect because while the yield strength increases, it does not automatically jump to the ultimate tensile strength unless the material was stressed up to that specific limit before unloading.
In a journal bearing, the radius of the friction circle increases with the increase in
A)
load
B)
radius of the journal
C)
speed of the journal
D)
viscosity of the lubricant
In a journal bearing, the 'friction circle' is an imaginary circle on the surface of the journal where the total frictional force is assumed to act. The radius of this friction circle (r) is typically expressed as a fraction of the journal radius (R), often denoted as r = kR. According to the theory of lubrication and bearing design, the position of the friction circle depends on the load carried by the bearing. As the load (W) increases, the pressure distribution in the lubricant film changes, and the point of application of the resultant frictional force shifts further away from the center of the journal. Therefore, the radius of the friction circle increases as the load increases.
Analyzing other options:
- Radius of the journal (b): While the friction circle radius is proportional to the journal radius, the question asks what causes it to 'increase' (implying a change in the operating condition or design parameter for a given bearing). The ratio k is primarily influenced by the load.
- Speed of the journal (c): Increasing speed generally increases the thickness of the oil film (hydrodynamic lift), which typically reduces the coefficient of friction and does not directly increase the friction circle radius in the same manner as load.
- Viscosity of the lubricant (d): Viscosity affects the friction torque and film thickness, but the primary driver for the shift in the resultant force location (the friction circle radius) is the applied load.
In the case of an involute toothed gear, involute starts from
A)
addendum circle
B)
dedendum circle
C)
pitch circle
D)
base circle
An involute curve is defined as the path traced by a point on a straight line that rolls without slipping on a circle. In gear geometry, this 'rolling circle' is known as the base circle. Therefore, the involute profile of a gear tooth physically begins at the base circle and extends outward toward the addendum circle.
Analysis of options:
- a. Addendum circle: This is the outermost circle of the gear; the involute ends here.
- b. Dedendum circle: This is the bottom-most circle of the tooth space; the profile here is usually a radial fillet curve, not an involute.
- c. Pitch circle: This is the theoretical circle used to define the gear ratio and kinematics; while the involute passes through it, it does not start there.
- d. Base circle: This is the fundamental circle from which the involute is generated. The involute profile starts exactly at the base circle.
Which gear is used for connecting two coplanar and intersecting shafts?
A)
Spur gear
B)
Helical gear
C)
Bevel gear
D)
None of these
To determine the correct gear type, we must analyze the spatial relationship between the two shafts: 1. Coplanar: The axes of the shafts lie in the same plane. 2. Intersecting: The axes meet at a specific point.
- Spur gears (Option a) are used for parallel shafts.
- Helical gears (Option b) are primarily used for parallel shafts (though crossed helical gears exist for non-parallel, non-intersecting shafts).
- Bevel gears (Option c) are specifically designed with conical shapes to transmit power between shafts that intersect, typically at a 90-degree angle, though other angles are possible. Because they are conical, their axes intersect at the apex of the cones, and they operate in a single plane relative to that intersection point.
Therefore, the Bevel gear is the only option that satisfies the condition of connecting intersecting shafts.
Which of the following cities were conferred with the cleanest city award under Swachh Survekshan Awards, 2023
A)
Bangaluru and Prayagraj
B)
Indore and Surat
C)
Prayagraj and Indore
D)
Surat and Bangaluru
Under the Swachh Survekshan Awards 2023 (announced in early 2024), for the first time, two cities shared the top spot for the cleanest city in India. Indore, which had previously held the title for several consecutive years, and Surat were jointly awarded the title of the cleanest city. This marked a significant milestone as Surat joined Indore at the top of the rankings based on their waste management and sanitation protocols. Therefore, option (b) is correct. Options (a), (c), and (d) are incorrect as Bengaluru and Prayagraj did not share the top 'cleanest city' title in the 2023 survey.
‘e-Kisan Upaj Nidhi’ (Digital Gateway) was launched by Shri Piyush Goyal to
A)
Prevent distress sale by farmers
B)
Provide financial assistance to small-scale farmers
C)
Facilitate access to healthcare services for rural farmers
D)
Promote Sustainable Development Goals
The 'e-Kisan Upaj Nidhi' is a digital gateway launched by the Government of India (introduced by Shri Piyush Goyal) specifically designed to provide a warehouse receipt financing system. The primary objective of this initiative is to allow farmers to store their produce in warehouses when market prices are low and use the warehouse receipts to obtain loans from banks. This prevents 'distress sales,' where farmers are forced to sell their crops immediately after harvest at very low prices due to a lack of storage facilities or immediate need for cash.
- Option (b) is incorrect because while it involves financing, it is specifically 'warehouse receipt financing' rather than general financial assistance.
- Option (c) is incorrect as the portal is related to agricultural commerce and finance, not healthcare.
- Option (d) is incorrect because while it may contribute to broader goals, the specific purpose of this portal is the prevention of distress sales through digital warehouse receipts.
The decrease in the general price level of goods and services is called
A)
Deflation
B)
Stagflation
C)
Devaluation
D)
Recession
Step-by-step reasoning:
1. The question asks for the term describing a decrease in the general price level of goods and services.
2. Deflation is defined as a sustained decrease in the general price level of goods and services in an economy over a period of time. It is the opposite of inflation.
3. Evaluating other options:
- Stagflation (b) is a condition characterized by slow economic growth, relatively high unemployment, and rising prices (inflation).
- Devaluation (c) is the deliberate downward adjustment of the value of a country's currency relative to another currency or standard.
- Recession (d) is a period of temporary economic decline during which trade and industrial activity are reduced, generally identified by a fall in GDP in two successive quarters.
Therefore, option (a) is the only correct term for a decrease in the general price level.
Who said ‘Live as if you were to die tomorrow, learn as if you were to live forever’?
A)
Swami Vivekananda
B)
Mahatma Gandhi
C)
Rabindranath Tagore
D)
BRAmbedkar
The quote 'Live as if you were to die tomorrow. Learn as if you were to live forever' is widely attributed to Mahatma Gandhi. It reflects his philosophy of mindfulness, urgency in living a virtuous life, and the lifelong pursuit of knowledge.
Analysis of other options:
- Swami Vivekananda focused on strength, spirituality, and the potential of the youth (e.g., 'Arise, awake, and stop not until the goal is reached').
- Rabindranath Tagore was a poet and philosopher known for his works on nature, humanity, and nationalism (e.g., Gitanjali).
- B.R. Ambedkar focused on social justice, equality, and the legal framework of India (e.g., 'Educate, Agitate, Organize').
The 128 Constitution Amendment Bill, 2023, is associated with?
A)
Reserve 33% of seats for women in Lok Sabha and State Assemblies
B)
Identify Other Backward Classes (OBCs)
C)
Reservation for Economically Weaker Sections (EWSs)
D)
Goods and Services Tax
The 128th Constitution Amendment Bill, 2023 (which became the 106th Constitution Amendment Act, 2023), is known as the 'Nari Shakti Vandan Adhiniyam'. Its primary objective is to reserve one-third (33%) of all seats for women in the Lok Sabha, the State Legislative Assemblies, and the Delhi Legislative Assembly.
Analysis of other options:
- Option (b): Identifying OBCs is generally handled by the National Commission for Backward Classes (NCBC) and state-level commissions, not by this specific amendment.
- Option (c): Reservation for Economically Weaker Sections (EWS) was introduced by the 103rd Constitution Amendment Act, 2019.
- Option (d): The Goods and Services Tax (GST) was introduced by the 101st Constitution Amendment Act, 2016.
India signs agreement for Lithium exploration and Mining project with
A)
Brazil
B)
Australia
C)
Argentina
D)
Chile
In January 2024, India signed a significant agreement with Argentina for the exploration and mining of lithium. The agreement was signed between KABIL (Khanij Bidesh India Ltd), a joint venture of three public sector undertakings (NALCO, HCL, and MECL), and the Argentine government. Argentina is part of the 'Lithium Triangle' (along with Chile and Bolivia), which holds some of the world's largest lithium reserves. This strategic move is aimed at securing a steady supply of lithium to support India's transition toward electric vehicles (EVs) and green energy storage. While Australia is a major lithium producer and Chile has vast reserves, the specific recent agreement for exploration and mining projects highlighted in current affairs for 2024 pertains to Argentina.
What are the constituents of solder alloy?
A)
Pb and Zn
B)
Pb and Sn
C)
Pb and Si
D)
Pb and Co
Solder is a fusible alloy used to create a permanent bond between metal workpieces, most commonly in electronics. The traditional and most common composition of solder is a mixture of Lead (Pb) and Tin (Sn).
1. **Lead (Pb)**: Provides strength and lowers the melting point of the alloy.
2. **Tin (Sn)**: Acts as the primary binding agent because it wets the surfaces of the metals being joined.
Common ratios include 60% Tin and 40% Lead (60/40 solder), which is favored for its low melting point and excellent flow characteristics.
Analysis of other options:
- Option (a) Pb and Zn: Lead and Zinc are not the primary constituents of standard solder.
- Option (c) Pb and Si: Silicon is a metalloid and does not form a fusible solder alloy with lead.
- Option (d) Pb and Co: Cobalt is a transition metal used in high-strength alloys, not in low-melting-point solders.
Thomas Cup is related to which among the following sports?
A)
Table Tennis
B)
Lawn Tennis
C)
Badminton
D)
Golf
The Thomas Cup is the world men's team championship in badminton. It is held every two years and is the counterpart to the Uber Cup, which is the world women's team championship in badminton.
Analysis of other options:
- Table Tennis: Major championships include the World Table Tennis Championships.
- Lawn Tennis: Major championships include the four Grand Slams (Australian Open, French Open, Wimbledon, and US Open) and the Davis Cup (men's team) and Billie Jean King Cup (women's team).
- Golf: Major championships include the Masters, U.S. Open, The Open Championship, and PGA Championship.
Arundhati Bhattacharya is the first woman Chairperson of
A)
ICICI
B)
SBI
C)
Axis Bank
D)
Canara Bank
Arundhati Bhattacharya served as the Chairperson of the State Bank of India (SBI) from October 1, 2013, to October 22, 2017. She was the first woman to hold this prestigious position in the history of India's largest public sector bank.
Analysis of other options:
- ICICI: While ICICI has had prominent women leaders (such as Chanda Kochhar as CEO), Arundhati Bhattacharya was not the first woman Chairperson of ICICI.
- Axis Bank and Canara Bank: She has never served as the Chairperson of these institutions.