GATE 2025 ME

All 65 questions of GATE 2025 ME

Question text and figures as in the official paper, with the answer from the official key. Worked solutions for every question are in your report after you take the paper as a 3-hour test.

Q1 · General Aptitude · MCQ · 1 mark

Fish : Shoal :: Lion : _______

Select the correct option to complete the analogy.

  • (A)
    Pride
  • (B)
    School
  • (C)
    Forest
  • (D)
    Series

Answer (official key): A

Worked solution: in your report after you take this paper.

Q2 · General Aptitude · MCQ · 1 mark

Identify the grammatically correct sentence:

  • (A)
    It is I who am responsible for this fiasco.
  • (B)
    It is myself who is responsible for this fiasco.
  • (C)
    It is I who is responsible for this fiasco.
  • (D)
    It is I who are responsible for this fiasco.

Answer (official key): A

Worked solution: in your report after you take this paper.

Q3 · General Aptitude · MCQ · 1 mark

Two cars, P and Q, start from a point X in India at 10 AM. Car P travels North with a speed of 2525 km/h and car Q travels East with a speed of 3030 km/h. Car P travels continuously but car Q stops for some time after travelling for one hour. If both the cars are at the same distance from X at 11:30 AM, for how long (in minutes) did car Q stop?

  • (A)
    1010
  • (B)
    1212
  • (C)
    1515
  • (D)
    1818

Answer (official key): C

Worked solution: in your report after you take this paper.

Q4 · General Aptitude · MCQ · 1 mark

The ceiling function of a real number xx, denoted by ce(x)ce(x), is defined as the smallest integer that is greater than or equal to xx. Similarly, the floor function, denoted by fl(x)fl(x), is defined as the largest integer that is smaller than or equal to xx. Which one of the following statements is NOT correct for all possible values of xx?

  • (A)
    ce(x)≥xce(x)\geq x
  • (B)
    fl(x)≤xfl(x)\leq x
  • (C)
    ce(x)≥fl(x)ce(x)\geq fl(x)
  • (D)
    fl(x)<ce(x)fl(x)<ce(x)

Answer (official key): D

Worked solution: in your report after you take this paper.

Q5 · General Aptitude · MCQ · 1 mark

P and Q play chess frequently against each other. Of these matches, P has won 80%80\% of the matches, drawn 15%15\% of the matches and lost 5%5\% of the matches.

If they play 33 more matches, what is the probability of P winning exactly 22 of these 33 matches?

  • (A)
    48125\frac{48}{125}
  • (B)
    16125\frac{16}{125}
  • (C)
    1625\frac{16}{25}
  • (D)
    2548\frac{25}{48}

Answer (official key): A

Read the worked solution

Q6 · General Aptitude · MCQ · 2 marks

Identify the option that has the most appropriate sequence such that a coherent paragraph is formed:

P. At once, without thinking much, people rushed towards the city in hordes with the sole aim of grabbing as much gold as they could.

Q. However, little did they realize about the impending hardships they would have to face on their way to the city: miles of mud, unfriendly forests, hungry beasts and inimical local lords – all of which would reduce their chances of getting gold to almost zero.

R. All of them thought that easily they could lay their hands on gold and become wealthy overnight.

S. About a hundred years ago, the news that gold had been discovered in Kolar spread like wildfire and the whole State was in raptures.

  • (A)
    P→Q→R→S\mathrm{P\to Q\to R\to S}
  • (B)
    Q→S→R→P\mathrm{Q\to S\to R\to P}
  • (C)
    S→Q→P→R\mathrm{S\to Q\to P\to R}
  • (D)
    S→P→R→Q\mathrm{S\to P\to R\to Q}

Answer (official key): D

Read the worked solution

Q7 · General Aptitude · MCQ · 2 marks

If HIDE and CAGE are coded as 19-23-7-11 and 5-2-17-11 respectively, then what is the code for HIGH?

  • (A)
    5-17-1-2
  • (B)
    17-19-13-17
  • (C)
    13-3-1-2
  • (D)
    19-23-17-19

Answer (official key): D

Worked solution: in your report after you take this paper.

Q8 · General Aptitude · MCQ · 2 marks

The given figure is reflected about the horizontal dashed line and then rotated clockwise by 90∘90^\circ about an axis perpendicular to the plane of the figure.

Which one of the following options correctly shows the resultant figure?

Note: The figures shown are representative.

Figure for GATE 2025 ME question 8 (Spatial Aptitude)

  • (A)
    GATE 2025 ME question 8 (Spatial Aptitude), option A
  • (B)
    GATE 2025 ME question 8 (Spatial Aptitude), option B
  • (C)
    GATE 2025 ME question 8 (Spatial Aptitude), option C
  • (D)
    GATE 2025 ME question 8 (Spatial Aptitude), option D

Answer (official key): B

Worked solution: in your report after you take this paper.

Q9 · General Aptitude · MCQ · 2 marks

Which one of the following options has the correct sequence of objects arranged in the increasing number of mirror lines (lines of symmetry)?

  • (A)
    Circle; Square; Equilateral triangle; Isosceles triangle
  • (B)
    Isosceles triangle; Equilateral triangle; Square; Circle
  • (C)
    Equilateral triangle; Isosceles triangle; Square; Circle
  • (D)
    Isosceles triangle; Square; Equilateral triangle; Circle

Answer (official key): B

Worked solution: in your report after you take this paper.

Q10 · General Aptitude · MCQ · 2 marks

A final year student appears for placement interview in two companies, S and T. Based on her interview performance, she estimates the probability of receiving job offers from companies S and T to be 0.80.8 and 0.60.6, respectively. Let pp be the probability that she receives job offers from both the companies. Select the most appropriate option.

  • (A)
    0≤p≤0.20\leq p\leq 0.2
  • (B)
    0.4≤p≤0.60.4\leq p\leq 0.6
  • (C)
    0.2≤p≤0.40.2\leq p\leq 0.4
  • (D)
    0.6≤p≤1.00.6\leq p\leq 1.0

Answer (official key): B

Worked solution: in your report after you take this paper.

Q11 · Linear Algebra · MCQ · 1 mark

Let A\mathbf{A} and B\mathbf{B} be real symmetric matrices of same size. Which one of the following options is correct?

  • (A)
    AT=A−1\mathbf{A}^{\mathrm{T}}=\mathbf{A}^{-1}
  • (B)
    AB=BA\mathbf{AB}=\mathbf{BA}
  • (C)
    (AB)T=BTAT(\mathbf{AB})^{\mathrm{T}}=\mathbf{B}^{\mathrm{T}}\mathbf{A}^{\mathrm{T}}
  • (D)
    A=A−1\mathbf{A}=\mathbf{A}^{-1}

Answer (official key): C

Worked solution: in your report after you take this paper.

Q12 · Differential Equations · MCQ · 1 mark

For the differential equation given below, which one of the following options is correct?

∂2u∂x2+∂2u∂y2=00≤x≤1, 0≤y≤1\frac{\partial^2u}{\partial x^2}+\frac{\partial^2u}{\partial y^2}=0\qquad 0\leq x\leq1,\ 0\leq y\leq1

  • (A)
    u=ex+yu=e^{x+y} is a solution for all xx and yy
  • (B)
    u=exsin⁡yu=e^x\sin y is a solution for all xx and yy
  • (C)
    u=sin⁡xsin⁡yu=\sin x\sin y is a solution for all xx and yy
  • (D)
    u=cos⁡xcos⁡yu=\cos x\cos y is a solution for all xx and yy

Answer (official key): B

Worked solution: in your report after you take this paper.

Q13 · Complex Variables · MCQ · 1 mark

The divergence of the curl of a vector field is

  • (A)
    the magnitude of this vector field
  • (B)
    the argument of this vector field
  • (C)
    the magnitude of the curl of this vector field
  • (D)
    zero

Answer (official key): D

Worked solution: in your report after you take this paper.

Q14 · Probability and Statistics · MCQ · 1 mark

If two unbiased coins are tossed, then what is the probability of having at least one head?

  • (A)
    0.250.25
  • (B)
    0.50.5
  • (C)
    0.6750.675
  • (D)
    0.750.75

Answer (official key): D

Worked solution: in your report after you take this paper.

Q15 · Heat Transfer · MCQ · 1 mark

Let a spherical block of ice at −7 ∘C-7\,^{\circ}\mathrm{C} be exposed to atmospheric air at 30 ∘C30\,^{\circ}\mathrm{C} with the gravitational direction as shown in the figure below. What will be the overall direction of air flow in this situation?

Figure for GATE 2025 ME question 15 (Heat Transfer)

  • (A)
    Upward
  • (B)
    Downward
  • (C)
    NO motion
  • (D)
    Sideward

Answer (official key): B

Read the worked solution

Q16 · Fluid Mechanics · MCQ · 1 mark

Consider two identical tanks with a bottom hole of diameter dd. One tank is filled with water and the other tank is filled with engine oil. The height of the fluid column hh is same in both the cases. The fluid exit velocity in the two tanks are V1V_1 and V2V_2. Neglecting all losses, which one of the following options is correct?

Figure for GATE 2025 ME question 16 (Fluid Mechanics)

  • (A)
    V2>V1V_2>V_1
  • (B)
    V2=V1V_2=V_1
  • (C)
    V2<V1V_2<V_1
  • (D)
    Insufficient data to definitively conclude the relationship between V1V_1 and V2V_2

Answer (official key): B

Worked solution: in your report after you take this paper.

Q17 · Fluid Mechanics · MCQ · 1 mark

In a laboratory experiment using a scaled down model to measure scour at a bridge pier, the Froude number is important. The ratio of the prototype length to the model length is 100100. If the velocity of the model is 1 m s−11\ \mathrm{m\ s^{-1}}, the velocity (in m s−1\mathrm{m\ s^{-1}}) of the prototype is

  • (A)
    0.10.1
  • (B)
    11
  • (C)
    1010
  • (D)
    100100

Answer (official key): C

Worked solution: in your report after you take this paper.

Q18 · Thermodynamics · MCQ · 1 mark

Air inside a rigid, thermally-insulated tank undergoes stirring as shown in the figure below. Which one of the following options is correct?

Figure for GATE 2025 ME question 18 (Thermodynamics)

  • (A)
    The enthalpy of the air increases while the entropy of the air remains constant
  • (B)
    Both the enthalpy and the entropy of the air remain constant
  • (C)
    Both the enthalpy and the entropy of the air increase
  • (D)
    The enthalpy of the air decreases while the entropy of the air increases

Answer (official key): C

Worked solution: in your report after you take this paper.

Q19 · Thermal Applications · MCQ · 1 mark

In a psychrometric chart, one axis represents dry-bulb temperature. The axis, that is perpendicular to the dry-bulb temperature axis, represents

  • (A)
    wet-bulb temperature
  • (B)
    specific humidity
  • (C)
    relative humidity
  • (D)
    enthalpy

Answer (official key): B

Worked solution: in your report after you take this paper.

Q20 · Engineering Materials · MCQ · 1 mark

Among the following surface hardening processes, steel is heated to the lowest temperature in

  • (A)
    carburizing
  • (B)
    cyaniding
  • (C)
    nitriding
  • (D)
    carbonitriding

Answer (official key): C

Worked solution: in your report after you take this paper.

Q21 · Manufacturing Engineering · MCQ · 1 mark

The welding process commonly used for fabricating tailor-welded blanks of dissimilar thickness for automotive applications is

  • (A)
    gas welding
  • (B)
    laser welding
  • (C)
    arc welding
  • (D)
    friction welding

Answer (official key): B

Worked solution: in your report after you take this paper.

Q22 · Mechanics of Materials · MCQ · 1 mark

The yield stress of a metal in uniaxial tension is 200200 MPa. According to von Mises yield criterion, the yield stress (in MPa) of the metal in pure shear is closest to

  • (A)
    115.5115.5
  • (B)
    100.0100.0
  • (C)
    66.766.7
  • (D)
    141.4141.4

Answer (official key): A

Worked solution: in your report after you take this paper.

Q23 · Manufacturing Engineering · MCQ · 1 mark

In computer aided design (CAD), solid models can be constructed using

  • (A)
    boundary representation (B-rep)
  • (B)
    Bezier curves
  • (C)
    B-splines
  • (D)
    nonuniform rational B-splines (NURBS)

Answer (official key): A

Worked solution: in your report after you take this paper.

Q24 · Manufacturing Engineering · MCQ · 1 mark

Ceramics and glass are machined by

  • (A)
    electric discharge machining
  • (B)
    ultrasonic machining
  • (C)
    electrochemical machining
  • (D)
    transferred arc plasma machining

Answer (official key): B

Worked solution: in your report after you take this paper.

Q25 · Manufacturing Engineering · MCQ · 1 mark

When assembled, the hole 30+0.000+0.03030^{+0.030}_{+0.000} mm and shaft 30−0.020+0.02030^{+0.020}_{-0.020} mm will result in

  • (A)
    loose fit
  • (B)
    interference fit
  • (C)
    transition fit
  • (D)
    clearance fit

Answer (official key): C

Worked solution: in your report after you take this paper.

Q26 · Applied Mechanics · MCQ · 1 mark

A rigid circular disc of radius rr (in m) is rolling without slipping on a flat surface as shown in the figure below. The angular velocity of the disc is ω\omega (in rad s−1\mathrm{rad\ s^{-1}}). The velocities (in m s−1\mathrm{m\ s^{-1}}) at points OO and AA, respectively, are

Figure for GATE 2025 ME question 26 (Applied Mechanics)

  • (A)
    rω i^r\omega\,\hat{i} and 0 i^0\,\hat{i}
  • (B)
    −rω i^-r\omega\,\hat{i} and 0 i^0\,\hat{i}
  • (C)
    −rω i^-r\omega\,\hat{i} and −rω i^-r\omega\,\hat{i}
  • (D)
    rω i^r\omega\,\hat{i} and rω i^r\omega\,\hat{i}

Answer (official key): A

Worked solution: in your report after you take this paper.

Q27 · Applied Mechanics · MCQ · 1 mark

A truss structure is loaded as shown in the figure below. Among the options given, which member in the truss is a zero-force member?

Figure for GATE 2025 ME question 27 (Applied Mechanics)

  • (A)
    BDBD
  • (B)
    BCBC
  • (C)
    BABA
  • (D)
    ADAD

Answer (official key): A

Worked solution: in your report after you take this paper.

Q28 · Mechanics of Materials · MCQ · 1 mark

A metallic square plate is subjected to a uniform hydrostatic pressure (P)(P). Choose the correct Mohr’s circle representing the state of stress at any point in the plate from the options given below.

For the Mohr’s circle, normal stress is positive towards right and shear stress is positive in the upward direction.

  • (A)
    GATE 2025 ME question 28 (Mechanics of Materials), option A
  • (B)
    GATE 2025 ME question 28 (Mechanics of Materials), option B
  • (C)
    GATE 2025 ME question 28 (Mechanics of Materials), option C
  • (D)
    GATE 2025 ME question 28 (Mechanics of Materials), option D

Answer (official key): B

Worked solution: in your report after you take this paper.

Q29 · Theory of Machines · MCQ · 1 mark

In the context of balancing of rotating and reciprocating masses, which one of the following options is true?

  • (A)
    An unbalanced rigid rotor can be completely balanced using a single balancing mass
  • (B)
    An unbalanced rigid rotor can be completely balanced using two balancing masses attached in two distinct planes
  • (C)
    A single-cylinder internal combustion engine can be completely balanced using a single balancing mass
  • (D)
    A single-cylinder internal combustion engine can be completely balanced using two balancing masses

Answer (official key): B

Worked solution: in your report after you take this paper.

Q30 · Machine Design · MCQ · 1 mark

A shaft carries a helical spur gear. Which one of the following bearings can NOT be used to support it?

  • (A)
    Angular contact bearing
  • (B)
    Double-row ball bearing
  • (C)
    Straight roller bearing
  • (D)
    Tapered roller bearing

Answer (official key): C

Worked solution: in your report after you take this paper.

Q31 · Numerical Methods · Numerical · 1 mark

The values of a function ff obtained for different values of xx are shown in the table below.

xx000.250.250.50.50.750.751.01.0
f(x)f(x)0.90.92.02.01.51.51.81.80.40.4

Using Simpson’s one-third rule,

∫01f(x) dx≈‾\int_0^1 f(x)\,dx\approx \underline{\hspace{2cm}}

(rounded off to 2 decimal places).

Answer (official key): 1.61 to 1.65

Read the worked solution

Q32 · Thermodynamics · Numerical · 1 mark

The thermal efficiency of an ideal air-standard Otto cycle is 0.50.5. The value of specific heat ratio of air is 1.41.4. The compression ratio of the cycle is ______________ (rounded off to 1 decimal place).

Answer (official key): 5.5 to 5.9

Worked solution: in your report after you take this paper.

Q33 · Manufacturing Engineering · Numerical · 1 mark

During a welding operation, thermal power of 25002500 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 55 mm while 65%65\% is absorbed within an inner concentric circle of radius 33 mm. The power density in the shaded area is _________ W mm−2\mathrm{W\ mm^{-2}} (rounded off to 2 decimal places).

Figure for GATE 2025 ME question 33 (Manufacturing Engineering)

Answer (official key): 9.92 to 9.98

Worked solution: in your report after you take this paper.

Q34 · Manufacturing Engineering · Numerical · 1 mark

A liquid metal is poured in a mold cavity of size 200 mm×200 mm×200 mm200\text{ mm}\times200\text{ mm}\times200\text{ 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).

Answer (official key): 189.8 to 190

Worked solution: in your report after you take this paper.

Q35 · Vibrations · Numerical · 1 mark

A block of mass 1 kg1\text{ kg} connected to a spring of stiffness 10 N m−110\text{ N m}^{-1} is operating in a viscous medium such that the damping ratio (or damping factor) is equal to the ratio of the damped frequency to the natural frequency. The magnitude of the damping ratio for this system is ________ (rounded off to 2 decimal places).

Answer (official key): 0.7 to 0.72

Worked solution: in your report after you take this paper.

Q36 · Calculus · MCQ · 2 marks

In the closed interval [0,3][0,3], the minimum value of the function ff given below is

f(x)=2x3−9x2+12xf(x)=2x^3-9x^2+12x

  • (A)
    00
  • (B)
    44
  • (C)
    55
  • (D)
    99

Answer (official key): A

Worked solution: in your report after you take this paper.

Q37 · Industrial Engineering · 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

Period1122334455667788991010
Actual demand425425415415420420430430427427418418422422416416426426421421
Forecast427427422422416416422422423423420420419419418418430430415415
  • (A)
    0.80.8 and 42.042.0
  • (B)
    0.80.8 and 4.24.2
  • (C)
    8.08.0 and 42.042.0
  • (D)
    8.08.0 and 4.24.2

Answer (official key): B

Worked solution: in your report after you take this paper.

Q38 · Manufacturing Engineering · MCQ · 2 marks

Match the mold elements in the casting process with the most suitable function

Mold elementFunction
PBlind riserICasting with internal cavity
QChillIIMolten metal reservoir
RSkim bobIIINucleating agent
SCoreIVAssisting in faster heat removal from melt
TInsulating sleeveVRemoval of impurities
UInoculantVIIncreasing the solidification time
  • (A)
    P-II, Q-IV, R-V, S-I, T-VI, U-III
  • (B)
    P-II, Q-V, R-VI, S-I, T-III, U-IV
  • (C)
    P-V, Q-I, R-VI, S-III, T-II, U-IV
  • (D)
    P-II, Q-IV, R-I, S-V, T-VI, U-III

Answer (official key): A

Worked solution: in your report after you take this paper.

Q39 · Manufacturing Engineering · 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

  • (A)
    51.251.2
  • (B)
    63.263.2
  • (C)
    75.075.0
  • (D)
    93.293.2

Answer (official key): B

Worked solution: in your report after you take this paper.

Q40 · Manufacturing Engineering · MCQ · 2 marks

In relation to additive manufacturing, match the following

ProcessLayer creation techniqueMaterial
PStereolithography1Injection of powder streamIPaper
QFused deposition modeling2Extrusion of melted polymerIIEpoxy
RLaminated object manufacturing3Liquid layer curingIIITitanium
SLaser-engineered net shaping4Sheet material depositionIVAcrylonitrile butadiene styrene (ABS)
  • (A)
    P-3-III, Q-1-IV, R-4-I, S-2-II
  • (B)
    P-3-II, Q-2-IV, R-4-I, S-1-III
  • (C)
    P-4-III, Q-2-IV, R-1-II, S-3-I
  • (D)
    P-3-II, Q-2-IV, R-1-I, S-4-III

Answer (official key): B

Worked solution: in your report after you take this paper.

Q41 · Manufacturing Engineering · MCQ · 2 marks

A plate of 30 mm30\text{ mm} thickness is fed through a rolling mill with two powered rolls. Each roll has a diameter of 500 mm500\text{ mm}. The plate thickness is to be reduced to 27 mm27\text{ mm} in a single pass. Assume no change in width. The process feasibility and the maximum draft (in mm) can be represented, respectively, as

Use the coefficient of friction as 0.120.12

  • (A)
    feasible and 3.63.6
  • (B)
    NOT feasible and 2.62.6
  • (C)
    feasible and 3.03.0
  • (D)
    NOT feasible and 6.06.0

Answer (official key): A

Worked solution: in your report after you take this paper.

Q42 · Vibrations · MCQ · 2 marks

The system shown in the figure below consists of a cantilever beam (with flexural rigidity EIEI and negligible mass), a spring (with spring constant KK and negligible mass) and a block of mass mm. Assuming a lumped parameter model for the system, the fundamental natural frequency (ωn)(\omega_n) of the system is

Figure for GATE 2025 ME question 42 (Vibrations)

  • (A)
    3EIL3+Km\sqrt{\frac{\frac{3EI}{L^3}+K}{m}}
  • (B)
    EIL3+Km\sqrt{\frac{\frac{EI}{L^3}+K}{m}}
  • (C)
    3EIL3+K2m\sqrt{\frac{\frac{3EI}{L^3}+K}{2m}}
  • (D)
    EIL3+K2m\sqrt{\frac{\frac{EI}{L^3}+K}{2m}}

Answer (official key): A

Worked solution: in your report after you take this paper.

Q43 · Machine Design · MCQ · 2 marks

The endurance limit of a specific grade of steel is same as its yield strength. The ultimate strength of this grade of steel is twice of its yield strength. A component made of this steel is loaded in tension and unloaded periodically. It is required that the component does NOT fail for at least 10610^6 loading cycles, as per the Soderberg law. Considering a factor of safety of 22, the maximum applied tensile principal stress is

  • (A)
    one-fourth of the endurance limit
  • (B)
    half of the endurance limit
  • (C)
    the endurance limit
  • (D)
    twice the endurance limit

Answer (official key): B

Worked solution: in your report after you take this paper.

Q44 · Fluid Mechanics · MSQ · 2 marks

For a fully-developed pipe flow, which of the following options is/are correct?

  • (A)
    For the same maximum velocity, the average velocity is higher in the turbulent regime than that of the laminar regime
  • (B)
    Compressibility effects are important if Mach number is less than 0.30.3
  • (C)
    For laminar flow, the friction factor is independent of surface roughness
  • (D)
    For laminar flow, friction factor decreases with decrease in Reynolds number

Answer (official key): A, C

Read the worked solution

Q45 · Complex Variables · Numerical · 2 marks

If CC is the unit circle in the complex plane with its center at the origin, then the value of nn in the equation given below is __________ (rounded off to 1 decimal place).

∮Cz3(z2+4)(z2−4) dz=2πin\oint_C\frac{z^3}{(z^2+4)(z^2-4)}\,dz=2\pi i n

Answer (official key): -0.1 to 0.1

Worked solution: in your report after you take this paper.

Q46 · Calculus · Numerical · 2 marks

The directional derivative of the function ff given below at the point (1,0)(1,0) in the direction of 12(i^+3j^)\frac{1}{2}(\hat{i}+\sqrt{3}\hat{j}) is ____________ (rounded off to 1 decimal place).

f(x,y)=x2+xy2f(x,y)=x^2+xy^2

Answer (official key): 0.9 to 1.1

Worked solution: in your report after you take this paper.

Q47 · Differential Equations · Numerical · 2 marks

Let yy be the solution of the differential equation with the initial conditions given below. If y(x=2)=Aln⁡2y(x=2)=A\ln 2, then the value of AA is ____________ (rounded off to 2 decimal places).

x2d2ydx2+3xdydx+y=0y(x=1)=0dydx(x=1)=1x^2\frac{d^2y}{dx^2}+3x\frac{dy}{dx}+y=0\qquad y(x=1)=0\qquad \frac{dy}{dx}(x=1)=1

Answer (official key): 0.45 to 0.55

Worked solution: in your report after you take this paper.

Q48 · Heat Transfer · Numerical · 2 marks

Consider a cylindrical furnace of 5 m5\text{ m} diameter and 5 m5\text{ m} length with bottom, top and curved surfaces maintained at uniform temperatures of 800 K800\text{ K}, 1500 K1500\text{ K} and 500 K500\text{ K}, respectively. The view factor between the bottom and top surfaces, F12F_{12} is 0.20.2. The magnitude of net radiation heat transfer rate between the bottom surface and the curved surface is _____________ kW (rounded off to 1 decimal place).

All surfaces of the furnace can be assumed as black.

The Stefan-Boltzmann constant, σ=5.67×10−8 W m−2 K−4\sigma=5.67\times10^{-8}\text{ W m}^{-2}\text{ K}^{-4}.

Figure for GATE 2025 ME question 48 (Heat Transfer)

Answer (official key): 308 to 310

Worked solution: in your report after you take this paper.

Q49 · Fluid Mechanics · Numerical · 2 marks

A pitot tube connected to a U-tube mercury manometer measures the speed of air flowing in the wind tunnel as shown in the figure below. The density of air is 1.23 kg m−31.23\text{ kg m}^{-3} while the density of water is 1000 kg m−31000\text{ kg m}^{-3}. For the manometer reading of h=30 mmh=30\text{ mm} of mercury, the speed of air in the wind tunnel is _____________ m s−1\text{m s}^{-1} (rounded off to 1 decimal place).

Assume: Specific gravity of mercury =13.6=13.6

Acceleration due to gravity =10 m s−2=10\text{ m s}^{-2}

Figure for GATE 2025 ME question 49 (Fluid Mechanics)

Answer (official key): 80 to 83

Worked solution: in your report after you take this paper.

Q50 · Fluid Mechanics · Numerical · 2 marks

Consider a velocity field V⃗=3z i^+0 j^+Cx k^\vec{V}=3z\,\hat{i}+0\,\hat{j}+Cx\,\hat{k}, where CC is a constant. If the flow is irrotational, the value of CC is _________ (rounded off to 1 decimal place).

Answer (official key): 2.9 to 3.1

Worked solution: in your report after you take this paper.

Q51 · Heat Transfer · Numerical · 2 marks

Water enters a tube of diameter, D=60 mmD=60\text{ mm} with mass flow rate of 0.01 kg s−10.01\text{ kg s}^{-1} as shown in the figure below. The inlet mean temperature is Tm,i=293 KT_{\mathrm{m,i}}=293\text{ K} and the uniform heat flux at the surface of the tube is 2000 W m−22000\text{ W m}^{-2}. For the exit mean temperature of Tm,o=353 KT_{\mathrm{m,o}}=353\text{ K}, the length of the tube, LL is ________ m (rounded off to 1 decimal place).

Use the specific heat of water as 4181 J kg−1 K−14181\text{ J kg}^{-1}\text{ K}^{-1}.

Figure for GATE 2025 ME question 51 (Heat Transfer)

Answer (official key): 6.5 to 6.8

Worked solution: in your report after you take this paper.

Q52 · Thermal Applications · Numerical · 2 marks

A thermal power plant is running with no reheat or regeneration. The specific enthalpy and specific entropy of steam at the turbine inlet are 3344 kJ kg−13344\text{ kJ kg}^{-1} and 6.5 kJ kg−1 K−16.5\text{ kJ kg}^{-1}\text{ K}^{-1}, respectively. The turbine isentropic efficiency is 0.90.9, and the mass flow rate of steam at the turbine inlet is 102 kg s−1102\text{ kg s}^{-1}. The turbine power output is _____________ MW (rounded off to 1 decimal place).

Properties of saturated liquid and saturated vapor at turbine exit pressure

Saturated liquid water: Specific enthalpy (kJ kg−1\text{kJ kg}^{-1})Saturated liquid water: Specific entropy (kJ kg−1 K−1\text{kJ kg}^{-1}\text{ K}^{-1})Saturated water vapor: Specific enthalpy (kJ kg−1\text{kJ kg}^{-1})Saturated water vapor: Specific entropy (kJ kg−1 K−1\text{kJ kg}^{-1}\text{ K}^{-1})
3413411.11.1264526457.67.6

Answer (official key): 98.5 to 101.5

Worked solution: in your report after you take this paper.

Q53 · Fluid Mechanics · Numerical · 2 marks

Consider a Pelton wheel of 1 m1\text{ m} diameter. The magnitude of relative velocity of water at the bucket inlet is same as the magnitude of relative velocity of water at the bucket exit. The absolute speed of water at the bucket inlet is 125.66 m s−1125.66\text{ m s}^{-1}. For maximum power output from the Pelton wheel, the rpm of the Pelton wheel is __________________ (rounded off to 1 decimal place).

Answer (official key): 1197 to 1203

Worked solution: in your report after you take this paper.

Q54 · Thermodynamics · Numerical · 2 marks

A thermodynamically closed system contains 1 kg1\text{ kg} of hydrogen. The system undergoes a reversible polytropic process with polytropic index 1.31.3. The work output during the process is 400 kJ400\text{ kJ}. During the process, hydrogen behaves as an ideal gas with constant specific heats. The absolute value of heat transfer during the process is ____________ kJ (rounded off to 1 decimal place).

Specific heat of hydrogen at constant pressure =14.56 kJ kg−1 K−1=14.56\text{ kJ kg}^{-1}\text{ K}^{-1}

Specific heat of hydrogen at constant volume =10.4 kJ kg−1 K−1=10.4\text{ kJ kg}^{-1}\text{ K}^{-1}

Answer (official key): 99 to 101

Worked solution: in your report after you take this paper.

Q55 · Thermal Applications · Numerical · 2 marks

A heat pump, operating in reversed Carnot cycle, maintains a steady air temperature of 300 K300\text{ K} inside an auditorium. The heat pump receives heat from the ambient air. The ambient air temperature is 280 K280\text{ K}. Heat loss from the auditorium is 15 kW15\text{ kW}. The power consumption of the heat pump is ____ kW (rounded off to 2 decimal places).

Answer (official key): 0.95 to 1.1

Worked solution: in your report after you take this paper.

Q56 · Mechanics of Materials · Numerical · 2 marks

The state of stress at a point is shown in the figure given below. Under plane stress assumption, the normal strain along the thickness direction (εzz)(\varepsilon_{zz}) is ____________ (rounded off to 2 decimal places).

Use the Young’s Modulus E=200 GPaE=200\text{ GPa} and Poisson’s ratio ν=0.27\nu=0.27.

Figure for GATE 2025 ME question 56 (Mechanics of Materials)

Answer (official key): -0.29 to -0.25 or 0.25 to 0.29

Worked solution: in your report after you take this paper.

Q57 · Mechanics of Materials · Numerical · 2 marks

A simply supported beam of length 1 m1\text{ m} is subjected to a uniformly distributed bending moment of 1 N m1\text{ N m} per m throughout the length as shown in the figure given below. The bending moment at the mid-point of the beam is _____ N m\text{N m} (rounded off to the nearest integer).

Figure for GATE 2025 ME question 57 (Mechanics of Materials)

Answer (official key): 0

Worked solution: in your report after you take this paper.

Q58 · Mechanics of Materials · Numerical · 2 marks

An isotropic brittle material is tested in the universal testing machine. The stress-strain diagram for the material shows a bi-linear elastic behavior as shown in the figure given below. The strain energy density is ________ MJ m−3\text{MJ m}^{-3} (rounded off to 2 decimal places).

Figure for GATE 2025 ME question 58 (Mechanics of Materials)

Answer (official key): 1 to 1.1

Worked solution: in your report after you take this paper.

Q59 · Theory of Machines · Numerical · 2 marks

A pair of spur gears is required to maintain a velocity ratio of 1:21:2. The module of the gears is 10 mm10\text{ mm} and the addendum is 10 mm10\text{ mm}. If the operating pressure angle is 15∘15^\circ, the minimum number of teeth required on the pinion to ensure NO interference/undercutting is ____ (answer in integer).

Answer (official key): 25

Worked solution: in your report after you take this paper.

Q60 · Theory of Machines · Numerical · 2 marks

An offset slider-crank mechanism is shown in the figure below. The length of the stroke of the slider is ______ mm (rounded off to nearest integer).

Figure for GATE 2025 ME question 60 (Theory of Machines)

Answer (official key): 61 to 63

Worked solution: in your report after you take this paper.

Q61 · Machine Design · Numerical · 2 marks

Two plates of thickness 10 mm10\text{ mm} each are to be joined by a transverse fillet weld on one side and the resulting structure is loaded as shown in the figure below.

If the ultimate tensile strength of the weld material is 150 MPa150\text{ MPa} and the factor of safety to be used is 33, the minimum length of the weld required to ensure that the weld does NOT fail is ______ mm (rounded off to 2 decimal places).

Figure for GATE 2025 ME question 61 (Machine Design)

Answer (official key): 12 to 14.2 or 18 to 28.4 or 32 to 34.2

Worked solution: in your report after you take this paper.

Q62 · Manufacturing Engineering · Numerical · 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).

Assume that solidification time follows Chvorinov’s rule with an exponent of 22.

Answer (official key): 0.83 to 0.87

Worked solution: in your report after you take this paper.

Q63 · Manufacturing Engineering · Numerical · 2 marks

Cylindrical workpieces of diameter 60 mm60\text{ mm} and length 400 mm400\text{ mm} are machined on a lathe at a cutting speed of 25 m min−125\text{ m min}^{-1} and a feed of 0.2 mm rev−10.2\text{ 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 33 minutes. With a labor and overhead cost of ₹ 55 per minute, the tool changing cost per piece is ₹ _______ (rounded off to 2 decimal places).

Answer (official key): 2.65 to 2.95

Worked solution: in your report after you take this paper.

Q64 · Industrial Engineering · Numerical · 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).

Order quantityUnit price (₹)
11 to 4994999.09.0
500500 to 9999998.58.5
10001000 or more8.08.0

Answer (official key): 26000 to 26100

Worked solution: in your report after you take this paper.

Q65 · Industrial Engineering · Numerical · 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).

ActivityImmediate predecessorDuration (hours)
A-44
BA88
CA55
DB22
EB77
FC66
GD33
HE, F, G99

Answer (official key): 2

Worked solution: in your report after you take this paper.