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Engineering Materials

7 Questions
GATE→2026→Materials, Manufacturing and Industrial Engineering→Engineering Materials
Q1
NAT[2 Marks]
A metal has FCC crystal structure with 2.71 g/cm32.71~g/cm^{3} of density and 26.98 g/mol26.98~g/mol of atomic weight. Avogadro's number is 6.023×10236.023 \times 10^{23}. The atomic radius of the metal is ____ nm (rounded off to 2 decimal places).
GATE→2025→Materials, Manufacturing and Industrial Engineering→Engineering Materials
Q2
MCQ[1 Mark]
Among the following surface hardening processes, steel is heated to the lowest temperature in
GATE→2024→Materials, Manufacturing and Industrial Engineering→Engineering Materials
Q3
MCQ[1 Mark]
The phases present in pearlite are
GATE→2023→Materials, Manufacturing and Industrial Engineering→Engineering Materials
Q4
NAT[2 Marks]
The atomic radius of a hypothetical face-centered cubic (FCC) metal is (2/10) nm(\sqrt{2}/10)~nm. The atomic weight of the metal is 24.092 g/mol24.092~g/mol. Taking Avogadro's number to be 6.023×1023 atoms/mol6.023\times 10^{23}~atoms/mol, the density of the metal is ____ kg/m3kg/m^{3}. (Answer in integer)
GATE→2023→Materials, Manufacturing and Industrial Engineering→Engineering Materials
Q5
NAT[2 Marks]
A steel sample with 1.5 wt.%1.5~wt.\% carbon (no other alloying elements present) is slowly cooled from 1100∘C1100^{\circ}C to just below the eutectoid temperature (723∘C)(723^{\circ}C). A part of the iron-cementite phase diagram is shown in the figure. The ratio of the pro-eutectoid cementite content to total cementite content in the microstructure that develops just below the eutectoid temperature is ____ (Rounded off to two decimal places)
Figure for Question 5
GATE→2022→Materials, Manufacturing and Industrial Engineering→Engineering Materials
Q6
MSQ[1 Mark]
Which of the following heat treatment processes is/are used for surface hardening of steels? (A) Carburizing (B) Cyaniding (C) Annealing (D) Carbonitriding
GATE→2022→Materials, Manufacturing and Industrial Engineering→Engineering Materials
Q7
NAT[2 Marks]
A 1 mm thick cylindrical tube, 100 mm in diameter, is orthogonally turned such that the entire wall thickness of the tube is cut in a single pass. The axial feed of the tool is 1 m/minute and the specific cutting energy (u) of the tube material is 6 J mmଷ ⁄ . Neglect contribution of feed force towards power. The power required to carry out this operation is _________ kW (round off to one decimal place).

Casting, Forming and Joining Processes

17 Questions
GATE→2026→Materials, Manufacturing and Industrial Engineering→Casting, Forming and Joining Processes
Q8
MCQ[1 Mark]
In relation to metal casting defects, match the following: | Description | Defect | | --- | --- | | P: Shallow blow found on a flat casting surface | I: Dross | | Q: Lighter impurities appearing on the top surface of a casting | II: Scab | | R: A rough, thin layer of metal, protruding above the casting surface, on top of a thin layer of sand | III: Scar | \nOptions:
Figure for Question 8
GATE→2026→Materials, Manufacturing and Industrial Engineering→Casting, Forming and Joining Processes
Q9
NAT[2 Marks]
In a deep drawing operation of a rectangular sheet metal, 30%30\% stretching in length results in 15%15\% reduction in thickness. Assuming volume constancy, the normal anisotropy of the sheet metal is ____ (rounded off to 2 decimal places).
GATE→2025→Materials, Manufacturing and Industrial Engineering→Casting, Forming and Joining Processes
Q10
MCQ[1 Mark]
The welding process commonly used for fabricating tailor-welded blanks of dissimilar thickness for automotive applications is
GATE→2025→Materials, Manufacturing and Industrial Engineering→Casting, Forming and Joining Processes
Q11
NAT[1 Mark]
During a welding operation, thermal power of 2500 W2500~W is incident normally on a metallic surface. As shown in the figure below (figure is NOT to scale), the heated area is circular. Out of the incident power, 85%85\% of the power is absorbed within a circle of radius 5 mm5~mm while 65%65\% is absorbed within an inner concentric circle of radius 3 mm3~mm. The power density in the shaded area is ____ W mm−2W~mm^{-2} (rounded off to 2 decimal places).
Figure for Question 11
GATE→2025→Materials, Manufacturing and Industrial Engineering→Casting, Forming and Joining Processes
Q12
NAT[1 Mark]
A liquid metal is poured in a mold cavity of size 200 mm×200 mm×200 mm200~mm \times 200~mm \times 200~mm. The cooling is uniform in all directions with NO additional compensation for shrinkage. Considering the volumetric shrinkage during solidification and solid contraction as 7%7\% and 8%8\% respectively, the length of the cube edge after cooling down to the room temperature is ____ mm (rounded off to 1 decimal place).
GATE→2025→Materials, Manufacturing and Industrial Engineering→Casting, Forming and Joining Processes
Q13
MCQ[2 Marks]
Match the mold elements in the casting process with the most suitable function: | Mold element | Function | | --- | --- | | P: Blind riser | I: Casting with internal cavity | | Q: Chill | II: Molten metal reservoir | | R: Skim bob | III: Nucleating agent | | S: Core | IV: Assisting in faster heat removal from melt | | T: Insulating sleeve | V: Removal of impurities | | U: Inoculant | VI: Increasing the solidification time |
GATE→2025→Materials, Manufacturing and Industrial Engineering→Casting, Forming and Joining Processes
Q14
MCQ[2 Marks]
Wire drawing operation is performed on a perfectly plastic metal without any strain hardening. Assuming no friction and no redundant work, the maximum possible percentage reduction in area in a single pass is closest to
GATE→2025→Materials, Manufacturing and Industrial Engineering→Casting, Forming and Joining Processes
Q15
MCQ[2 Marks]
A plate of 30 mm30~mm thickness is fed through a rolling mill with two powered rolls. Each roll has a diameter of 500 mm500~mm. The plate thickness is to be reduced to 27 mm27~mm in a single pass. Assume no change in width. The process feasibility and the maximum draft (in mm) can be represented, respectively, as\nUse the coefficient of friction as 0.120.12
GATE→2025→Materials, Manufacturing and Industrial Engineering→Casting, Forming and Joining Processes
Q16
NAT[2 Marks]
Two metal parts (a cylinder and a cube) of same volume are cast under identical conditions. The diameter of the cylinder is equal to its height. The ratio of the solidification time of the cube to that of the cylinder is ____ (rounded off to 2 decimal places).\nAssume that solidification time follows Chvorinov's rule with an exponent of 2.
GATE→2024→Materials, Manufacturing and Industrial Engineering→Casting, Forming and Joining Processes
Q17
MCQ[1 Mark]
The 'Earing' phenomenon in metal forming is associated with
GATE→2024→Materials, Manufacturing and Industrial Engineering→Casting, Forming and Joining Processes
Q18
MCQ[1 Mark]
The allowance provided to a pattern for easy withdrawal from a sand mold is
GATE→2024→Materials, Manufacturing and Industrial Engineering→Casting, Forming and Joining Processes
Q19
MCQ[1 Mark]
The most suitable electrode material used for joining low alloy steels using Gas Metal Arc Welding (GMAW) process is
GATE→2024→Materials, Manufacturing and Industrial Engineering→Casting, Forming and Joining Processes
Q20
NAT[2 Marks]
Aluminium is casted in a cube-shaped mold having dimensions as 20 mm×20 mm×20 mm20~mm \times 20~mm \times 20~mm. Another mold of the same mold material is used to cast a sphere of aluminium having a diameter of 20 mm20~mm. The pouring temperature for both cases is the same. The ratio of the solidification times of the cube-shaped mold to the spherical mold is ____ (answer in integer).
GATE→2024→Materials, Manufacturing and Industrial Engineering→Casting, Forming and Joining Processes
Q21
NAT[2 Marks]
A blanking operation is performed on C20 steel sheet to obtain a circular disc having a diameter of 20 mm20~mm and a thickness of 2 mm2~mm. An allowance of 0.040.04 is provided. The punch size used for the operation is ____ mm (rounded off to 2 decimal places).
GATE→2024→Materials, Manufacturing and Industrial Engineering→Casting, Forming and Joining Processes
Q22
NAT[2 Marks]
In an arc welding process, the voltage and current are 30 V30~V and 200 A200~A, respectively. The cross-sectional area of the joint is 20 mm220~mm^{2} and the welding speed is 5 mm/s5~mm/s. The heat required to melt the material is 200 J/s200~J/s. The percentage of heat lost to the surrounding during the welding process is ____ (rounded off to 2 decimal places). [Note: Official Key marked this as MTA (Marks To All)]
GATE→2023→Materials, Manufacturing and Industrial Engineering→Casting, Forming and Joining Processes
Q23
MSQ[1 Mark]
Two surfaces P and Q are to be joined together. In which of the given joining operation(s), there is no melting of the two surfaces P and Q for creating the joint?
GATE→2023→Materials, Manufacturing and Industrial Engineering→Casting, Forming and Joining Processes
Q24
MSQ[1 Mark]
In a metal casting process to manufacture parts, both patterns and moulds provide shape by dictating where the material should or should not go. Which of the option(s) given correctly describe(s) the mould and the pattern?

Machining and Machine Tool Operations

12 Questions
GATE→2026→Materials, Manufacturing and Industrial Engineering→Machining and Machine Tool Operations
Q25
MCQ[1 Mark]
A work piece is to be firmly held in a fixture. It is to be machined by using a plain slab milling cutter as shown in the figure below. Which one of the following options is the most suitable value of height H of the fixture in mm?
Figure for Question 25
GATE→2026→Materials, Manufacturing and Industrial Engineering→Machining and Machine Tool Operations
Q26
NAT[2 Marks]
During orthogonal turning by using a single point cutting tool, feed rate is 0.24 mm/rev0.24~mm/rev. The uncut chip thickness is 0.23 mm0.23~mm. The shear angle, tangential force component, and radial force component are 20∘20^{\circ}, 800 N800~N, and 150 N150~N, respectively. The value of shear force is ____ N (rounded off to 2 decimal places).
GATE→2026→Materials, Manufacturing and Industrial Engineering→Machining and Machine Tool Operations
Q27
NAT[2 Marks]
A drill bit during its lifetime can produce 150 through holes in a plate at a drill-speed of 200 RPM200~RPM. If the drill-speed increases to 300 RPM300~RPM, then it can produce 60 through holes in the same plate before the drill bit fails. Assume all other parameters remain constant. The value of the exponent in Taylor's tool life equation is ____ (rounded off to 2 decimal places).
GATE→2025→Materials, Manufacturing and Industrial Engineering→Machining and Machine Tool Operations
Q28
MCQ[1 Mark]
Ceramics and glass are machined by
GATE→2025→Materials, Manufacturing and Industrial Engineering→Machining and Machine Tool Operations
Q29
NAT[2 Marks]
Cylindrical workpieces of diameter 60 mm60~mm and length 400 mm400~mm are machined on a lathe at a cutting speed of 25 m min−125~m~min^{-1} and a feed of 0.2 mm rev−10.2~mm~rev^{-1}. The Taylor's tool life parameters CC and nn for this setup are 7575 and 0.250.25, respectively. The tool changing time is 3 minutes3~minutes. With a labor and overhead cost of $5 per minute, the tool changing cost per piece is ____ (rounded off to 2 decimal places).
GATE→2024→Materials, Manufacturing and Industrial Engineering→Machining and Machine Tool Operations
Q30
MCQ[1 Mark]
The grinding wheel used to provide the best surface finish is
GATE→2024→Materials, Manufacturing and Industrial Engineering→Machining and Machine Tool Operations
Q31
NAT[2 Marks]
A cutting tool provides a tool life of 60 minutes60~minutes while machining with the cutting speed of 60 m/min60~m/min. When the same tool is used for machining the same material, it provides a tool life of 10 minutes10~minutes for a cutting speed of 100 m/min100~m/min. If the cutting speed is changed to 80 m/min80~m/min for the same tool and work material combination, the tool life computed using Taylor's tool life model is ____ minutes (rounded off to 2 decimal places).
GATE→2024→Materials, Manufacturing and Industrial Engineering→Machining and Machine Tool Operations
Q32
NAT[2 Marks]
A flat surface of a C60 steel having dimensions of 100 mm100~mm (length) ×200 mm\times 200~mm (width) is produced by a HSS slab mill cutter. The 8-toothed cutter has 100 mm100~mm diameter and 200 mm200~mm width. The feed per tooth is 0.1 mm0.1~mm, cutting velocity is 20 m/min20~m/min and depth of cut is 2 mm2~mm. The machining time required to remove the entire stock is ____ minutes (rounded off to 2 decimal places).
GATE→2023→Materials, Manufacturing and Industrial Engineering→Machining and Machine Tool Operations
Q33
MCQ[2 Marks]
In an ideal orthogonal cutting experiment (see figure), the cutting speed V is 1 m/s1~m/s, the rake angle of the tool α=5∘\alpha=5^{\circ} and the shear angle, ϕ\phi, is known to be 45∘45^{\circ}. Applying the ideal orthogonal cutting model, consider two shear planes PQ and RS close to each other. As they approach the thin shear zone (shown as a thick line in the figure), plane RS gets sheared with respect to PQ (point R1 shears to R2, and S1 shears to S2). Assuming that the perpendicular distance between PQ and RS is δ=25 μm\delta=25~\mu m, what is the value of shear strain rate (in s−1s^{-1}) that the material undergoes at the shear zone?
Figure for Question 33
GATE→2022→Materials, Manufacturing and Industrial Engineering→Machining and Machine Tool Operations
Q34
MCQ[1 Mark]
Which one of the following is NOT a form of inventory? (A) Raw materials (B) Work-in-process materials (C) Finished goods (D) CNC Milling Machines
GATE→2022→Materials, Manufacturing and Industrial Engineering→Machining and Machine Tool Operations
Q35
MSQ[1 Mark]
Which of the following additive manufacturing technique(s) can use a wire as a feedstock material? (A) Stereolithography (B) Fused deposition modeling (C) Selective laser sintering (D) Directed energy deposition processes
GATE→2022→Materials, Manufacturing and Industrial Engineering→Machining and Machine Tool Operations
Q36
NAT[1 Mark]
Electrochemical machining operations are performed with tungsten as the tool, and copper and aluminum as two different workpiece materials. Properties of copper and aluminum are given in the table below. Material Atomic mass (amu) Valency Density (g/cm3) Copper 63 2 9 Aluminum 27 3 2.7 Ignore overpotentials, and assume that current efficiency is 100% for both the workpiece materials. Under identical conditions, if the material removal rate (MRR) of copper is 100 mg/s, the MRR of aluminum will be ________________ mg/s (round-off to two decimal places). 𝑟 G A 𝑅 𝑔

Additive Manufacturing

3 Questions
GATE→2026→Materials, Manufacturing and Industrial Engineering→Additive Manufacturing
Q37
MCQ[1 Mark]
Which one of the following options is NOT an error associated with STereoLithography (STL) file in additive manufacturing?
GATE→2025→Materials, Manufacturing and Industrial Engineering→Additive Manufacturing
Q38
MCQ[2 Marks]
In relation to additive manufacturing, match the following: | Process | Layer creation technique | Material | | --- | --- | --- | | P: Stereolithography | 1: Injection of powder stream | I: Paper | | Q: Fused deposition modeling | 2: Extrusion of melted polymer | II: Epoxy | | R: Laminated object manufacturing | 3: Liquid layer curing | III: Titanium | | S: Laser-engineered net shaping | 4: Sheet material deposition | IV: Acrylonitrile butadiene styrene (ABS) |
GATE→2023→Materials, Manufacturing and Industrial Engineering→Additive Manufacturing
Q39
NAT[2 Marks]
A solid part (see figure) of polymer material is to be fabricated by additive manufacturing (AM) in square-shaped layers starting from the bottom of the part working upwards. The nozzle diameter of the AM machine is a/10 mma/10~mm and the nozzle follows a linear serpentine path parallel to the sides of the square layers with a feed rate of a/5 mm/mina/5~mm/min.\nIgnore any tool path motions other than those involved in adding material, and any other delays between layers or the serpentine scan lines.\nThe time taken to fabricate this part is ____ minutes. (Answer in integer) [Note: Official Key marked this as MTA (Marks To All)]
Figure for Question 39

Metrology and Inspection

6 Questions
GATE→2026→Materials, Manufacturing and Industrial Engineering→Metrology and Inspection
Q40
MCQ[1 Mark]
A two-dimensional surface profile is obtained over a sampling length by using a contact type stylus profilometer as shown in the figure below. A line AA parallel to the general lay of the trace is considered. The true heights from AA to the peaks and valleys (in μm)(in~\mu m) in the trace are also shown in the figure. The ten-point height average in μm\mu m is
Figure for Question 40
GATE→2025→Materials, Manufacturing and Industrial Engineering→Metrology and Inspection
Q41
MCQ[1 Mark]
When assembled, the hole 30−0.000+0.030 mm30_{-0.000}^{+0.030}~mm and shaft 30−0.020+0.02030_{-0.020}^{+0.020} [Wait, source shows 30−0.02030_{-0.020}] mm will result in
GATE→2023→Materials, Manufacturing and Industrial Engineering→Metrology and Inspection
Q42
MCQ[1 Mark]
A cuboidal part has to be accurately positioned first, arresting six degrees of freedom and then clamped in a fixture, to be used for machining. Locating pins in the form of cylinders with hemi-spherical tips are to be placed on the fixture for positioning. Four different configurations of locating pins are proposed as shown. Which one of the options given is correct?
GATE→2023→Materials, Manufacturing and Industrial Engineering→Metrology and Inspection
Q43
NAT[2 Marks]
A part, produced in high volumes, is dimensioned as shown. The machining process making this part is known to be statistically in control based on sampling data. The sampling data shows that D1 follows a normal distribution with a mean of 20 mm20~mm and a standard deviation of 0.3 mm0.3~mm, while D2 follows a normal distribution with a mean of 35 mm35~mm and a standard deviation of 0.4 mm0.4~mm. An inspection of dimension C is carried out in a sufficiently large number of parts. To be considered under six-sigma process control, the upper limit of dimension C should be ____ mm. (Rounded off to one decimal place)
Figure for Question 43
GATE→2023→Materials, Manufacturing and Industrial Engineering→Metrology and Inspection
Q44
NAT[2 Marks]
A coordinate measuring machine (CMM) is used to determine the distance between Surface SP and Surface SQ of an approximately cuboidal shaped part. Surface SP is declared as the datum as per the engineering drawing used for manufacturing this part. The CMM is used to measure four points P1, P2, P3, P4 on Surface SP, and four points Q1, Q2, Q3, Q4 on Surface SQ as shown. A regression procedure is used to fit the necessary planes. The distance between the two fitted planes is ____ mm. (Answer in integer)
Figure for Question 44
GATE→2022→Materials, Manufacturing and Industrial Engineering→Metrology and Inspection
Q45
NAT[1 Mark]
A rigid uniform annular disc is pivoted on a knife edge A in a uniform gravitational field as shown, such that it can execute small amplitude simple harmonic motion in the plane of the figure without slip at the pivot point. The inner radius 𝑟 and outer radius 𝑅 are such that 𝑟ଶ= 𝑅ଶ/2, and the acceleration due to gravity is 𝑔. If the time period of small amplitude simple harmonic motion is given by 𝑇= 𝛽𝜋ඥ𝑅/𝑔, where 𝜋 is the ratio of circumference to diameter of a circle, then 𝛽= ________ (round off to 2 decimal places).
Figure for Question 45

Computer Aided Manufacturing and Automation

4 Questions
GATE→2026→Materials, Manufacturing and Industrial Engineering→Computer Aided Manufacturing and Automation
Q46
MCQ[2 Marks]
Consider the Euler variables of polyhedral objects namely, P1, P2, P3, and P4 given in the table below. | Polyhedral objects | Faces (F) | Edges (E) | Vertices (V) | Faces' inner loops (L) | Bodies (B) | Genus (G) | | --- | --- | --- | --- | --- | --- | --- | | P1 | 6 | 12 | 8 | 0 | 1 | 0 | | P2 | 5 | 8 | 5 | 0 | 1 | 0 | | P3 | 8 | 12 | 6 | 0 | 1 | 2 | | P4 | 10 | 24 | 16 | 0 | 1 | 0 | \nWhich one of the following options is NOT a topologically valid closed polyhedral object as per Euler's law?
Figure for Question 46
GATE→2025→Materials, Manufacturing and Industrial Engineering→Computer Aided Manufacturing and Automation
Q47
MCQ[1 Mark]
In computer aided design (CAD), solid models can be constructed using
GATE→2024→Materials, Manufacturing and Industrial Engineering→Computer Aided Manufacturing and Automation
Q48
MCQ[1 Mark]
The preparatory functions in Computer Numerical Controlled (CNC) machine programming are denoted by the alphabet
GATE→2023→Materials, Manufacturing and Industrial Engineering→Computer Aided Manufacturing and Automation
Q49
MCQ[2 Marks]
A CNC machine has one of its linear positioning axes as shown in the figure, consisting of a motor rotating a lead screw, which in turn moves a nut horizontally on which a table is mounted. The motor moves in discrete rotational steps of 50 steps per revolution. The pitch of the screw is 5 mm and the total horizontal traverse length of the table is 100 mm. What is the total number of controllable locations at which the table can be positioned on this axis?
Figure for Question 49

Production Planning and Control

8 Questions
GATE→2026→Materials, Manufacturing and Industrial Engineering→Production Planning and Control
Q50
MCQ[2 Marks]
Four jobs are on order in a factory. As on day 20 of the production calendar, corresponding due date and work remaining to complete these jobs (in days) are given in the table below. | Job | Due date | Work remaining (in days) | | --- | --- | --- | | M | 26 | 5 | | N | 24 | 10 | | O | 28 | 10 | | P | 31 | 5 | \nWhich job(s) has/have critical ratio less than unity?
GATE→2026→Materials, Manufacturing and Industrial Engineering→Production Planning and Control
Q51
NAT[2 Marks]
The actual demand for castings in a factory is 500 units and 635 units for the months of January 2026 and February 2026, respectively. The forecasted demand for January 2026 is 250 units and smoothing constant is 0.70.7. Using the exponential smoothing method, the forecast of the demand for castings in March 2026 is ____ units (in integer).
GATE→2026→Materials, Manufacturing and Industrial Engineering→Production Planning and Control
Q52
NAT[2 Marks]
The inventory holding cost of an item is 0.50perunitpermonthandtheorderingcostperorderis0.50 per unit per month and the ordering cost per order is550. A stockist needs to supply 10000 units of the item per year to the customers. Assume demand is fixed and shortage cost is infinite. Using classical economic order quantity (EOQ) model, the optimal lot size is ____ units per order (rounded off to nearest integer).
GATE→2025→Materials, Manufacturing and Industrial Engineering→Production Planning and Control
Q53
MCQ[2 Marks]
Considering the actual demand and the forecast for a product given in the table below, the mean forecast error and the mean absolute deviation, respectively, are | Period | Actual demand | Forecast | | --- | --- | --- | | 1 | 425 | 427 | | 2 | 421 | 423 | | 3 | 416 | 420 | | 4 | 418 | 422 | | 5 | 415 | 416 | | 6 | 420 | 422 | | 7 | 430 | 415 | | 8 | 418 | 430 | | 9 | 427 | 418 | | 10 | 426 | 419 |
GATE→2025→Materials, Manufacturing and Industrial Engineering→Production Planning and Control
Q54
NAT[2 Marks]
A company uses 30003000 units of a part annually. The units are priced as given in the table below. It costs 150150 to place an order. Carrying costs are 4040 percent of the purchase price per unit on an annual basis. The minimum total annual cost is ____ (rounded off to 1 decimal place). | Unit price | Order quantity | | --- | --- | | 9.0 | 1 to 499 | | 8.5 | 500 to 999 | | 8.0 | 1000 or more |
GATE→2024→Materials, Manufacturing and Industrial Engineering→Production Planning and Control
Q55
MCQ[1 Mark]
A set of jobs U, V, W, X, Y, Z arrive at time t=0t=0 to a production line consisting of two workstations in series. Each job must be processed by both workstations in sequence (i.e., the first followed by the second). The process times (in minutes) for each job on each workstation in the production line are given below. | Job | U | V | W | X | Y | Z | | --- | --- | --- | --- | --- | --- | --- | | Workstation 1 | 5 | 7 | 3 | 4 | 6 | 8 | | Workstation 2 | 4 | 6 | 6 | 8 | 5 | 7 | \nThe sequence in which the jobs must be processed by the production line if the total makespan of production is to be minimized is [Note: Official Key marked this as MTA (Marks To All)]
GATE→2024→Materials, Manufacturing and Industrial Engineering→Production Planning and Control
Q56
MCQ[2 Marks]
A company orders gears in conditions identical to those considered in the economic order quantity (EOQ) model in inventory control. The annual demand is 80008000 gears, the cost per order is 300300 rupees, and the holding cost is 1212 rupees per month per gear. The company uses an order size that is 25%25\% more than the optimal order quantity determined by the EOQ model. The percentage change in the total cost of ordering and holding inventory from that associated with the optimal order quantity is
GATE→2023→Materials, Manufacturing and Industrial Engineering→Production Planning and Control
Q57
MCQ[1 Mark]
With reference to the Economic Order Quantity (EOQ) model, which one of the options given is correct?
Figure for Question 57

Operations Research

12 Questions
GATE→2026→Materials, Manufacturing and Industrial Engineering→Operations Research
Q58
MCQ[2 Marks]
An objective function Z of primal variables (x1x_{1} and x2x_{2}) is described below:\nMinimize Z=0.07 x1+0.05 x2Z=0.07~x_{1}+0.05~x_{2}\nsubject to 0.1 x1≥0.40.1~x_{1}\ge0.4 0.1 x2≥0.60.1~x_{2}\ge0.6 0.1 x1+0.2 x2≥2.00.1~x_{1}+0.2~x_{2}\ge2.0 0.2 x1+0.1 x2≥1.80.2~x_{1}+0.1~x_{2}\ge1.8 x1,x2≥0x_{1},x_{2}\ge0 WW is the objective function of the dual of ZZ. k1,k2,k3,k_{1}, k_{2}, k_{3}, and k4k_{4} represent the corresponding dual variables. Which one of the following options represents the correct form of WW?
GATE→2026→Materials, Manufacturing and Industrial Engineering→Operations Research
Q59
NAT[2 Marks]
The activities of a PERT network and their corresponding activity time estimates (in weeks) i.e., optimistic (tot_{o}), most likely (tmt_{m}), and pessimistic (tpt_{p}) are given in the table below. | Activity | tot_{o} | tmt_{m} | tpt_{p} | | --- | --- | --- | --- | | 1-2 | 2 | 4 | 12 | | 1-3 | 2 | 4 | 6 | | 1-4 | 3 | 4 | 11 | | 2-5 | 3 | 6 | 9 | | 3-4 | 2 | 5 | 14 | | 3-5 | 3 | 3 | 3 | | 4-5 | 3 | 6 | 15 | | 5-6 | 2 | 5 | 8 | \nThe expected project length is ____ weeks (in integer).
GATE→2025→Materials, Manufacturing and Industrial Engineering→Operations Research
Q60
NAT[2 Marks]
A project involves eight activities with the precedence relationship and duration as shown in the table below. The slack for the activity D is ____ hours (answer in integer). | Activity | Immediate predecessor | Duration (hours) | | --- | --- | --- | | A | - | 4 | | B | A | 8 | | C | A | 5 | | D | B | 2 | | E | B | 7 | | F | C | 6 | | G | D | 3 | | H | E, F, G | 9 |
GATE→2024→Materials, Manufacturing and Industrial Engineering→Operations Research
Q61
MCQ[1 Mark]
A queueing system has one single server workstation that admits an infinitely long queue. The rate of arrival of jobs to the queueing system follows the Poisson distribution with a mean of 5 jobs/hour. The service time of the server is exponentially distributed with a mean of 6 minutes. In steady state operation of the queueing system, the probability that the server is not busy at any point in time is
GATE→2024→Materials, Manufacturing and Industrial Engineering→Operations Research
Q62
MCQ[2 Marks]
At the current basic feasible solution (bfs) v0v_{0}, the simplex method yields the following form of a linear programming problem in standard form. z=−x1−2x2z=-x_{1}-2x_{2} x3=2+2x1−x2x_{3}=2+2x_{1}-x_{2} x4=7+x1−2x2x_{4}=7+x_{1}-2x_{2} x5=3−x1x_{5}=3-x_{1} x1,x2,x3,x4,x5≥0x_{1}, x_{2}, x_{3}, x_{4}, x_{5}\ge0\nis written as a function of the non-basic variables. If the simplex method moves to the adjacent bfs v1v_{1} that best improves the objective function, which of the following represents the objective function at v1v_{1}, assuming that the objective function is written in the same manner as above?
GATE→2024→Materials, Manufacturing and Industrial Engineering→Operations Research
Q63
NAT[2 Marks]
In a supplier-retailer supply chain, the demand of each retailer, the capacity of each supplier, and the unit cost in rupees of material supply from each supplier to each retailer are tabulated below. The supply chain manager wishes to minimize the total cost of transportation across the supply chain. | | Retailer I | Retailer II | Retailer III | Retailer IV | Capacity | | --- | --- | --- | --- | --- | --- | | Supplier A | 11 | 16 | 19 | 13 | 300 | | Supplier B | 5 | 10 | 7 | 8 | 300 | | Supplier C | 12 | 14 | 17 | 11 | 300 | | Supplier D | 8 | 15 | 11 | 9 | 300 | | Demand | 300 | 300 | 300 | 300 | | \nThe optimal cost of satisfying the total demand from all retailers is ____ rupees (answer in integer).
GATE→2023→Materials, Manufacturing and Industrial Engineering→Operations Research
Q64
MCQ[1 Mark]
Which one of the options given represents the feasible region of the linear programming model:\nMaximize 45X1+60X245X_{1}+60X_{2} X1≤45X_{1}\le 45 X2≤50X_{2}\le 50 10X1+10X2≥60010X_{1}+10X_{2}\ge 600 25X1+5X2≤75025X_{1}+5X_{2}\le 750
Figure for Question 64
GATE→2022→Materials, Manufacturing and Industrial Engineering→Operations Research
Q65
MCQ[1 Mark]
- 35 Carry ONE mark each.
GATE→2022→Materials, Manufacturing and Industrial Engineering→Operations Research
Q66
MCQ[1 Mark]
Solution of ∇ଶ𝑇= 0 in a square domain (0 < 𝑥< 1 and 0 < 𝑦< 1) with boundary conditions: 𝑇(𝑥, 0) = 𝑥; 𝑇(0, 𝑦) = 𝑦; 𝑇(𝑥, 1) = 1 + 𝑥; 𝑇(1, 𝑦) = 1 + 𝑦 is (A) 𝑇(𝑥, 𝑦) = 𝑥−𝑥𝑦+ 𝑦 (B) 𝑇(𝑥, 𝑦) = 𝑥+ 𝑦 (C) 𝑇(𝑥, 𝑦) = −𝑥+ 𝑦 (D) 𝑇(𝑥, 𝑦) = 𝑥+ 𝑥𝑦+ 𝑦
Figure for Question 66
GATE→2022→Materials, Manufacturing and Industrial Engineering→Operations Research
Q67
MCQ[1 Mark]
In a linear programming problem, if a resource is not fully utilized, the shadow price of that resource is (A) positive (B) negative (C) zero (D) infinity
GATE→2022→Materials, Manufacturing and Industrial Engineering→Operations Research
Q68
MCQ[2 Marks]
Activities A to K are required to complete a project. The time estimates and the immediate predecessors of these activities are given in the table. If the project is to be completed in the minimum possible time, the latest finish time for the activity G is ____________ hours. Activity Time (hours) Immediate predecessors A 2 ─ B 3 ─ C 2 ─ D 4 A E 5 B F 4 B G 3 C H 10 D, E I 5 F J 8 G K 3 H, I, J (A) 5 (B) 10 (C) 8 (D) 9
GATE→2022→Materials, Manufacturing and Industrial Engineering→Operations Research
Q69
NAT[2 Marks]
An assignment problem is solved to minimize the total processing time of four jobs (1, 2, 3 and 4) on four different machines such that each job is processed exactly by one machine and each machine processes exactly one job. The minimum total processing time is found to be 500 minutes. Due to a change in design, the processing time of Job 4 on each machine has increased by 20 minutes. The revised minimum total processing time will be _____________ minutes (in integer).