GATE XE (Engineering Sciences) 2023 Question Paper & Solutions

Attempt the GATE XE (Engineering Sciences) 2023 previous year paper in real CBT exam mode or practice mode with the official answer key. Step-by-step explanations are coming soon.

All GATE XE (Engineering Sciences) papers

87 questions. Answers are shown only where the official answer key is available.

General Aptitude

Question 1

Marks: 1

The village was nestled in a green spot, _______ the ocean and the hills.

  • A. through
  • B. in
  • C. at
  • D. between

Answer: D. between

Question 2

Marks: 1

Disagree : Protest : : Agree : _______ (By word meaning)

  • A. Refuse
  • B. Pretext
  • C. Recommend
  • D. Refute

Answer: C. Recommend

Question 3

Marks: 1

A β€˜frabjous’ number is defined as a 3 digit number with all digits odd, and no two adjacent digits being the same. For example, 137 is a frabjous number, while 133 is not. How many such frabjous numbers exist?

  • A. 125
  • B. 720
  • C. 60
  • D. 80

Answer: D. 80

Question 4

Marks: 1

Which one among the following statements must be TRUE about the mean and the median of the scores of all candidates appearing for GATE 2023?

  • A. The median is at least as large as the mean.
  • B. The mean is at least as large as the median.
  • C. At most half the candidates have a score that is larger than the median.
  • D. At most half the candidates have a score that is larger than the mean.

Answer: C. At most half the candidates have a score that is larger than the median.

Question 5

Marks: 1

In the given diagram, ovals are marked at different heights (h) of a hill. Which one of the following options P, Q, R, and S depicts the top view of the hill?

Figure for question 5, GATE XE (Engineering Sciences) 2023

  • A. P
  • B. Q
  • C. R
  • D. S

Answer: B. Q

Question 6

Marks: 2

Residency is a famous housing complex with many well-established individuals among its residents. A recent survey conducted among the residents of the complex revealed that all of those residents who are well established in their respective fields happen to be academicians. The survey also revealed that most of these academicians are authors of some best-selling books. Based only on the information provided above, which one of the following statements can be logically inferred with certainty?

  • A. Some residents of the complex who are well established in their fields are also authors of some best-selling books.
  • B. All academicians residing in the complex are well established in their fields.
  • C. Some authors of best-selling books are residents of the complex who are well established in their fields.
  • D. Some academicians residing in the complex are well established in their fields.

Question 7

Marks: 2

Ankita has to climb 5 stairs starting at the ground, while respecting the following rules: 1. At any stage, Ankita can move either one or two stairs up. 2. At any stage, Ankita cannot move to a lower step. Let 𝐹(𝑁) denote the number of possible ways in which Ankita can reach the π‘π‘‘β„Ž stair. For example, 𝐹(1) = 1, 𝐹(2) = 2, 𝐹(3) = 3. The value of 𝐹(5) is _______.

  • A. 8
  • B. 7
  • C. 6
  • D. 5

Answer: A. 8

Question 8

Marks: 2

The information contained in DNA is used to synthesize proteins that are necessary for the functioning of life. DNA is composed of four nucleotides: Adenine (A), Thymine (T), Cytosine (C), and Guanine (G). The information contained in DNA can then be thought of as a sequence of these four nucleotides: A, T, C, and G. DNA has coding and non-coding regions. Coding regionsβ€”where the sequence of these nucleotides are read in groups of three to produce individual amino acidsβ€”constitute only about 2% of human DNA. For example, the triplet of nucleotides CCG codes for the amino acid glycine, while the triplet GGA codes for the amino acid proline. Multiple amino acids are then assembled to form a protein. Based only on the information provided above, which of the following statements can be logically inferred with certainty? (i) The majority of human DNA has no role in the synthesis of proteins. (ii) The function of about 98% of human DNA is not understood.

  • A. only (i)
  • B. only (ii)
  • C. both (i) and (ii)
  • D. neither (i) nor (ii)

Answer: D. neither (i) nor (ii)

Question 9

Marks: 2

Which one of the given figures P, Q, R and S represents the graph of the following function? 𝑓(π‘₯) = | |π‘₯+ 2| βˆ’|π‘₯βˆ’1| |

Figure for question 9, GATE XE (Engineering Sciences) 2023

  • A. P
  • B. Q
  • C. R
  • D. S

Answer: A. P

Question 10

Marks: 2

An opaque cylinder (shown below) is suspended in the path of a parallel beam of light, such that its shadow is cast on a screen oriented perpendicular to the direction of the light beam. The cylinder can be reoriented in any direction within the light beam. Under these conditions, which one of the shadows P, Q, R, and S is NOT possible?

Figure for question 10, GATE XE (Engineering Sciences) 2023

  • A. P
  • B. Q
  • C. R
  • D. S

Answer: D. S

Engineering Mathematics

Question 11

Marks: 1

Let 𝐴 be a 3 Γ— 3 real matrix having eigenvalues 1, 2, and 3. If 𝐡= 𝐴2 + 2𝐴+ 𝐼, where 𝐼 is the 3 Γ— 3 identity matrix, then the eigenvalues of 𝐡 are

  • A. 4, 9, 16
  • B. 1, 2, 3
  • C. 1, 4, 9
  • D. 4, 16, 25

Answer: A. 4, 9, 16

Question 12

Marks: 1

Let 𝑓: ℝ2 →ℝ be a function defined by 𝑓(π‘₯, 𝑦) = { π‘₯𝑦 |π‘₯| + 𝑦 , π‘¦β‰ βˆ’|π‘₯| 0 , otherwise. Then which one of the following statement is TRUE?

  • A. 𝑓 is NOT continuous at (0,0).
  • B. πœ•π‘“ πœ•π‘₯(0,0) = 0, and πœ•π‘“ πœ•π‘¦(0,0) = 1.
  • C. πœ•π‘“ πœ•π‘₯(0,0) = 1, and πœ•π‘“ πœ•π‘¦(0,0) = 0.
  • D. πœ•π‘“ πœ•π‘₯(0,0) = 1, and πœ•π‘“ πœ•π‘¦(0,0) = 1.

Answer: A. 𝑓 is NOT continuous at (0,0).

Question 13

Marks: 1

If the quadrature formula βˆ«π‘“(π‘₯)𝑑π‘₯ 1 βˆ’1 β‰ˆ1 9 (𝑐1𝑓(βˆ’1) + 𝑐2𝑓(1 2) + 𝑐3𝑓(1)) is exact for all polynomials of degree less than or equal to 2, then

  • A. 𝑐1 + 𝑐2 4 + 𝑐3 = 6
  • B. 𝑐1 + 𝑐2 3 + 𝑐3 = 4
  • C. 𝑐1 + 𝑐2 2 + 𝑐3 = 2
  • D. 𝑐1 + 𝑐2 + 𝑐3 = 5

Answer: A. 𝑐1 + 𝑐2 4 + 𝑐3 = 6

Question 14

Marks: 1

The second smallest eigenvalue of the eigenvalue problem 𝑑2𝑦 𝑑π‘₯2 + (πœ†βˆ’3)𝑦= 0, 𝑦(0) = 𝑦(πœ‹) = 0, is

  • A. 4
  • B. 3
  • C. 7
  • D. 9

Answer: C. 7

Question 15

Marks: 1

Which one of the following functions is differentiable at 𝑧= 0 but NOT differentiable at any other point in the complex plane β„‚?

  • A. 𝑓(𝑧) = 𝑧|𝑧|, π‘§βˆˆβ„‚
  • B. 𝑓(𝑧) = sin(𝑧), π‘§βˆˆβ„‚
  • C. 𝑓(𝑧) = {𝑒 1 𝑧, 𝑧≠0 0, 𝑧= 0 for π‘§βˆˆβ„‚
  • D. 𝑓(𝑧) = π‘’βˆ’π‘§2, π‘§βˆˆβ„‚

Answer: A. 𝑓(𝑧) = 𝑧|𝑧|, π‘§βˆˆβ„‚

Question 16

Type: NAT | Marks: 1

If the polynomial 𝑃(π‘₯) = π‘Ž0 + π‘Ž1π‘₯+ π‘Ž2π‘₯(π‘₯βˆ’1) + π‘Ž3π‘₯(π‘₯βˆ’1)(π‘₯βˆ’2) interpolates the points (0, 2), (1, 3), (2, 2), and (3, 5), then the value of 𝑃( 5 2) is _________ (round off to 2 decimal places).

Answer: 2.60 to 2.65

Question 17

Type: NAT | Marks: 1

The value of π‘š for which the vector field 𝐹⃗(π‘₯, 𝑦) = (4π‘₯π‘šπ‘¦2 βˆ’2 π‘₯ π‘¦π‘š)𝑖̂ + (2π‘₯4π‘¦βˆ’3π‘₯2𝑦2)𝑗̂ is a conservative vector field, is _________________ (in integer).

Answer: 3

Question 18

Marks: 2

Let 𝑃= [ 4 βˆ’2 2 6 βˆ’3 4 3 βˆ’2 3 ], and 𝑄= [ 3 βˆ’2 2 4 βˆ’4 6 2 βˆ’3 5 ] . The eigenvalues of both 𝑃 and 𝑄 are 1, 1, and 2. Which one of the following statements is TRUE?

  • A. Both 𝑃 and 𝑄 are diagonalizable
  • B. 𝑃 is diagonalizable but 𝑄 is NOT diagonalizable
  • C. 𝑃 is NOT diagonalizable but 𝑄 is diagonalizable
  • D. Both 𝑃 and 𝑄 are NOT diagonalizable

Answer: B. 𝑃 is diagonalizable but 𝑄 is NOT diagonalizable

Question 19

Marks: 2

The surface area of the portion of the paraboloid 𝑧= π‘₯2 + 𝑦2 that lies between the planes 𝑧= 0 and 𝑧= 1 4 is

  • A. πœ‹ 6 (2√2 βˆ’1)
  • B. πœ‹ 2 (2√2 βˆ’1)
  • C. πœ‹(2√2 βˆ’1)
  • D. πœ‹ 3 (2√2 βˆ’1)

Answer: A. πœ‹ 6 (2√2 βˆ’1)

Question 20

Type: NAT | Marks: 2

The probability of a person telling the truth is 4 6 . An unbiased die is thrown by the same person twice and the person reports that the numbers appeared in both the throws are same. Then the probability that actually the numbers appeared in both the throws are same is __________ (round off to 2 decimal places).

Answer: 0.26 to 0.30

Question 21

Type: NAT | Marks: 2

Let 𝑒(π‘₯, 𝑑) be the solution of the initial boundary value problem πœ•π‘’ πœ•π‘‘βˆ’ πœ•2𝑒 πœ•π‘₯2 = 0, π‘₯∈(0, 2), 𝑑> 0 𝑒(π‘₯, 0) = sin(πœ‹π‘₯), π‘₯∈(0, 2) 𝑒(0, 𝑑) = 𝑒(2, 𝑑) = 0. Then the value of π‘’πœ‹2 (𝑒( 1 2 , 1) βˆ’π‘’( 3 2 , 1)) is __________ (in integer).

Answer: 2

Fluid Mechanics

Question 22

Marks: 1

Match the following measuring instruments with the appropriate figures. I – Pitot probe II – Pitot-static probe III – Piezometer

Figure for question 22, GATE XE (Engineering Sciences) 2023

  • A. I – P; II – Q; III – R
  • B. I – R; II – Q; III – P
  • C. I – R; II – P; III – Q
  • D. I – Q; II – P; III – R

Answer: B. I – R; II – Q; III – P

Question 23

Marks: 1

Among the following non-dimensional numbers, which one characterizes periodicity present in a transient flow?

  • A. Froude number
  • B. Strouhal number
  • C. Peclet number
  • D. Lewis number

Answer: B. Strouhal number

Question 24

Marks: 1

For an incompressible boundary layer flow over a flat plate shown in the figure, the momentum thickness is expressed as

Figure for question 24, GATE XE (Engineering Sciences) 2023

  • A. ∫ 𝑒 π‘ˆβˆž 𝑑𝑦 ∞ 0
  • B. ∫ (1 βˆ’π‘’ π‘ˆβˆž ) 𝑑𝑦 ∞ 0
  • C. ∫ 𝑒 π‘ˆβˆž (1 βˆ’π‘’ π‘ˆβˆž ) 𝑑𝑦 ∞ 0
  • D. ∫ (1 βˆ’π‘’2 π‘ˆβˆž2 ) 𝑑𝑦 ∞ 0

Answer: C. ∫ 𝑒 π‘ˆβˆž (1 βˆ’π‘’ π‘ˆβˆž ) 𝑑𝑦 ∞ 0

Question 25

Marks: 1

Among the shear stress versus shear strain rate curves shown in the figure, which one corresponds to a shear thinning fluid?

Figure for question 25, GATE XE (Engineering Sciences) 2023

  • A. P
  • B. Q
  • C. R
  • D. S

Answer: C. R

Question 26

Marks: 1

Consider steady incompressible flow over a flat plate, where the dashed line represents the edge of the boundary layer, as shown in the figure. Which one among the following statements is true?

Figure for question 26, GATE XE (Engineering Sciences) 2023

  • A. Bernoulli’s equation can be applied in Region I between any two arbitrary points.
  • B. Bernoulli’s equation can be applied in Region I only along a streamline.
  • C. Bernoulli’s equation cannot be applied in Region II.
  • D. Bernoulli’s equation cannot be applied in Region I.

Answer: D. Bernoulli’s equation cannot be applied in Region I.

Question 27

Marks: 1

An inviscid steady incompressible flow is formed by combining a uniform flow with velocity π‘ˆβˆž and a clockwise vortex of strength 𝐾 at the origin, as shown in the figure. Velocity potential (πœ™) for the combined flow in polar coordinate (π‘Ÿ, πœƒ) is

Figure for question 27, GATE XE (Engineering Sciences) 2023

  • A. πœ™= πΎπœƒ 2 πœ‹βˆ’π‘ˆβˆžπ‘Ÿ cos πœƒ
  • B. πœ™= πΎπœƒ 2 πœ‹βˆ’π‘ˆβˆžπ‘Ÿ sin πœƒ
  • C. πœ™= 𝐾ln π‘Ÿ+ π‘ˆβˆžπ‘Ÿ cos πœƒ
  • D. πœ™= βˆ’πΎln π‘Ÿ+ π‘ˆβˆžπ‘Ÿ sin πœƒ

Answer: A. πœ™= πΎπœƒ 2 πœ‹βˆ’π‘ˆβˆžπ‘Ÿ cos πœƒ

Question 28

Marks: 1

Which of the following statements are true? (i) Conservation of mass for an unsteady incompressible flow can be represented as βˆ‡β‹…π‘‰βƒ—βƒ—= 0, where 𝑉⃗⃗ denotes velocity vector. (ii) Circulation is defined as the line integral of vorticity about a closed curve. (iii) For some fluids, shear stress can be a nonlinear function of the shear strain rate. (iv) Integration of the Bernoulli’s equation along a streamline under steady-state leads to the Euler’s equation.

  • A. (i), (ii) and (iv) only
  • B. (i), (ii) and (iii) only
  • C. (i) and (iii) only
  • D. (ii) and (iv) only

Answer: C. (i) and (iii) only

Question 29

Marks: 1

For a two-dimensional flow field given as 𝑉⃗⃗= βˆ’π‘₯𝑖̂ + 𝑦𝑗̂, a streamline passes through points (2, 1) and (5, p). The value of p is

  • A. 5
  • B. 5/2
  • C. 2/5
  • D. 2

Answer: C. 2/5

Question 30

Type: MSQ | Marks: 1

A stationary object is fully submerged in a static fluid, as shown in the figure. Here, CG and CB stand for center of gravity and center of buoyancy, respectively. Which one(s) among the following statements is/are true?

Figure for question 30, GATE XE (Engineering Sciences) 2023

  • A. The object is in stable equilibrium if 𝑦𝐢𝐺> 𝑦𝐢𝐡.
  • B. The object is in stable equilibrium if 𝑦𝐢𝐺< 𝑦𝐢𝐡.
  • C. The object is in neutral equilibrium if 𝑦𝐢𝐺= 𝑦𝐢𝐡.
  • D. The object is in unstable equilibrium if 𝑦𝐢𝐺= 𝑦𝐢𝐡.

Answer: A. The object is in stable equilibrium if 𝑦𝐢𝐺> 𝑦𝐢𝐡.; C. The object is in neutral equilibrium if 𝑦𝐢𝐺= 𝑦𝐢𝐡.

Question 31

Marks: 2

Consider steady fully-developed incompressible flow of a Newtonian fluid between two infinite parallel flat plates. The plates move in the opposite directions, as shown in the figure. In the absence of body force and pressure gradient, the ratio of shear stress at the top surface (𝑦= 𝐻) to that at the bottom surface (𝑦= 0) is

Figure for question 31, GATE XE (Engineering Sciences) 2023

  • A. 1
  • B. π‘ˆ1 π‘ˆ2
  • C. π‘ˆ1 βˆ’π‘ˆ2 π‘ˆ2
  • D. π‘ˆ1 + π‘ˆ2 π‘ˆ2

Answer: A. 1

Question 32

Marks: 2

A two-dimensional incompressible flow field is defined as, 𝑉⃗⃗(π‘₯, 𝑦) = (𝐴π‘₯𝑦) 𝑖̂ + (𝐡𝑦2) 𝑗̂ where, 𝐴 and 𝐡 are constants. The dynamic viscosity of the Newtonian fluid is πœ‡. In the absence of body force, which among the following expressions represents the pressure gradient at the location (5, 0) in the concerned flow field?

  • A. πœ‡π΄(5 𝑖̂ + 𝑗̂)
  • B. πœ‡(βˆ’5𝐡 𝑖̂ + 𝐴 𝑗̂)
  • C. πœ‡π΄(βˆ’π‘—Μ‚)
  • D. πœ‡π΄(5 𝑖̂)

Answer: C. πœ‡π΄(βˆ’π‘—Μ‚)

Question 33

Marks: 2

For a potential flow, the fluid velocity is given by 𝑉⃗⃗(π‘₯, 𝑦) = 𝑒𝑖̂ + 𝑣𝑗̂ . The slope of the potential line at (π‘₯, 𝑦) is

  • A. 𝑒 𝑣
  • B. 𝑣 𝑒
  • C. βˆ’π‘’ 𝑣
  • D. βˆ’π‘£ 𝑒

Answer: C. βˆ’π‘’ 𝑣

Question 34

Marks: 2

Consider steady incompressible flow of a Newtonian fluid over a horizontal flat plate, as shown in the figure. The boundary layer thickness is proportional to

Figure for question 34, GATE XE (Engineering Sciences) 2023

  • A. π‘₯1/4
  • B. π‘₯1/2
  • C. π‘₯βˆ’1/2
  • D. π‘₯2

Answer: B. π‘₯1/2

Question 35

Type: MSQ | Marks: 2

In a steady two-dimensional compressible flow, 𝑒 and 𝑣 are the π‘₯- and 𝑦- components of flow velocity, respectively and 𝜌 is the fluid density. Among the following pairs of relations, which one(s) perfectly satisfies/satisfy the definition of stream function, πœ“, for this flow?

  • A. 𝑒= πœ•πœ“ πœ•π‘¦ and 𝑣= βˆ’ πœ•πœ“ πœ•π‘₯
  • B. 𝑒= βˆ’ πœ•πœ“ πœ•π‘₯ and 𝑣= βˆ’ πœ•πœ“ πœ•π‘¦
  • C. πœŒπ‘’= πœ•πœ“ πœ•π‘¦ and πœŒπ‘£= βˆ’ πœ•πœ“ πœ•π‘₯
  • D. πœŒπ‘’= βˆ’ πœ•πœ“ πœ•π‘¦ and πœŒπ‘£= πœ•πœ“ πœ•π‘₯

Answer: C. πœŒπ‘’= πœ•πœ“ πœ•π‘¦ and πœŒπ‘£= βˆ’ πœ•πœ“ πœ•π‘₯; D. πœŒπ‘’= βˆ’ πœ•πœ“ πœ•π‘¦ and πœŒπ‘£= πœ•πœ“ πœ•π‘₯

Question 36

Type: NAT | Marks: 2

A water jet (density = 1000 kg/m3) is approaching a vertical plate, having an orifice at the center, as shown in the figure. While a part of the jet passes through the orifice, remainder flows along the plate. Neglect friction and assume both the inlet and exit jets to have circular cross-sections. If V = 5 m/s, 𝐷 = 100 mm and 𝑑 = 25 mm, magnitude of the horizontal force (in N, rounded off to one decimal place) required to hold the plate in its position is ___________.

Figure for question 36, GATE XE (Engineering Sciences) 2023

Answer: 183.0 to 185.0

Question 37

Type: NAT | Marks: 2

Water (density = 1000 kg/m3) and alcohol (specific gravity = 0.7) enter a Y-shaped channel at flow rates of 0.2 m3/s and 0.3 m3/s, respectively. Their mixture leaves through the other end of the channel, as shown in the figure. The average density (in kg/m3) of the mixture is _______.

Figure for question 37, GATE XE (Engineering Sciences) 2023

Answer: 820

Question 38

Type: NAT | Marks: 2

The velocity and acceleration of a fluid particle are given as 𝑉⃗⃗= (βˆ’π‘–Μ‚ + 2𝑗̂) m/s and π‘Žβƒ—= (βˆ’2𝑖̂ βˆ’4𝑗̂) m/s2, respectively. The magnitude of the component of acceleration (in m/s2, rounded off to two decimal places) of the fluid particle along the streamline is _______.

Answer: 2.60 to 2.75

Question 39

Type: NAT | Marks: 2

A hydraulic turbine with rotor diameter of 100 mm produces 200 W of power while rotating at 300 rpm. Another dynamically-similar turbine rotates at a speed of 1500 rpm. Consider both turbines to operate with the same fluid (identical density and viscosity), and neglect any gravitational effect. Then the power (in W, rounded off to nearest integer) produced by the second turbine is _______________.

Answer: 430 to 460

Question 40

Type: NAT | Marks: 2

Water (density = 1000 kg/m3) flows steadily with a flow rate of 0.05 m3/s through a venturimeter having throat diameter of 100 mm. If the pipe diameter is 200 mm and losses are negligible, the pressure drop (in kPa, rounded off to one decimal place) between an upstream location in the pipe and the throat (both at the same elevation) is _______.

Answer: 18.5 to 19.5

Question 41

Type: NAT | Marks: 2

Water flows around a thin flat plate (0.25 m long, 2 m wide) with a free stream velocity (π‘ˆβˆž) of 1 m/s, as shown in the figure. Consider linear velocity profile ( 𝑒 π‘ˆβˆž= 𝑦 𝛿) for which the laminar boundary layer thickness is expressed as 𝛿= 3.5π‘₯ βˆšπ‘…π‘’π‘₯ . For water, density = 1000 kg/m3 and dynamic viscosity = 0.001 kg/m.s. Net drag force (in N, rounded off to two decimal places) acting on the plate, neglecting the end effects, is ________.

Figure for question 41, GATE XE (Engineering Sciences) 2023

Answer: 1.10 to 1.20

Question 42

Type: NAT | Marks: 2

Axial velocity profile 𝑒(π‘Ÿ) for an axisymmetric flow through a circular tube of radius 𝑅 is given as, 𝑒(π‘Ÿ) π‘ˆ = (1 βˆ’π‘Ÿ 𝑅) 1 𝑛 ⁄ where π‘ˆ is the centerline velocity. If 𝑉 refers to the area-averaged velocity (volume flow rate per unit area), then the ratio 𝑉/π‘ˆ for 𝑛= 1 (rounded off to two decimal places) is ______________.

Answer: 0.32 to 0.34

Question 43

Type: NAT | Marks: 2

A stationary circular pipe of radius 𝑅= 0.5 m is half filled with water (density = 1000 kg/m3), whereas the upper half is filled with air at atmospheric pressure, as shown in the figure. Acceleration due to gravity is 𝑔= 9.81 m/s2. The magnitude of the force per unit length (in kN/m, rounded off to one decimal place) applied by water on the pipe section AB is _______. Material Science (XE-C)

Figure for question 43, GATE XE (Engineering Sciences) 2023

Answer: 2.2 to 2.4

Solid Mechanics

Question 66

Marks: 1

A plane truss is simply supported at P and R as shown. A downward force F is applied at hinge Q. The axial force developed in member PS is

Figure for question 66, GATE XE (Engineering Sciences) 2023

  • A. √5 2 𝐹 Tensile
  • B. √5 2 𝐹 Compressive
  • C. √5 𝐹 Tensile
  • D. √5 𝐹 Compressive

Answer: B. √5 2 𝐹 Compressive

Question 67

Marks: 1

A massless rigid rod OP of length L is hinged frictionlessly at O. A concentrated mass m is attached to end P of the rod. Initially, the rod OP is horizontal. Then, it is released from rest. There is gravity as shown. The rod acquires an angular velocity as it swings. The clockwise angular velocity of the rod, when it first reaches the vertical position as shown, is

Figure for question 67, GATE XE (Engineering Sciences) 2023

  • A. 2βˆšπ‘” 𝐿
  • B. √ 2 𝑔 𝐿
  • C. βˆšπ‘” 𝐿
  • D. 1 2 βˆšπ‘” 𝐿

Answer: B. √ 2 𝑔 𝐿

Question 68

Marks: 1

Two equivalent descriptions of the state of stress at a point are shown in the figure. The normal stresses 𝜎1 and 𝜎2 as shown on the right must be, respectively,

Figure for question 68, GATE XE (Engineering Sciences) 2023

  • A. 𝜏o and βˆ’πœo
  • B. βˆ’πœo and 𝜏o
  • C. 𝜏o √2 and βˆ’ 𝜏o √2
  • D. βˆ’ 𝜏o √2 and 𝜏o √2

Answer: A. 𝜏o and βˆ’πœo

Question 69

Marks: 1

The state of strain at a point in a machine component is given as πœ€π‘₯π‘₯= 2.5 Γ— 10βˆ’4, πœ€π‘¦π‘¦= 2.0 Γ— 10βˆ’4, πœ€π‘§π‘§= βˆ’1.5 Γ— 10βˆ’4, πœ€π‘₯𝑦= 2.5 Γ— 10βˆ’4, πœ€π‘¦π‘§= βˆ’0.5 Γ— 10βˆ’4, πœ€π‘§π‘₯= βˆ’1.0 Γ— 10βˆ’4. The volumetric strain at this point is

  • A. 4 Γ— 10βˆ’4
  • B. 3 Γ— 10βˆ’4
  • C. βˆ’5 Γ— 10βˆ’4
  • D. βˆ’3 Γ— 10βˆ’4

Answer: B. 3 Γ— 10βˆ’4

Question 70

Marks: 1

A thin walled, closed cylindrical vessel of inside diameter 𝑑 and wall thickness 𝑑 contains a fluid under pressure 𝑝. The figure below shows a part of the cylindrical vessel; end caps are not shown. Consider the small element shown with sides parallel and perpendicular to the axis of the cylinder. The stresses 𝜎1 and 𝜎2 are

Figure for question 70, GATE XE (Engineering Sciences) 2023

  • A. 𝜎1 = 𝑝𝑑 2𝑑; 𝜎2 = 𝑝𝑑 4𝑑
  • B. 𝜎1 = 𝑝𝑑 𝑑; 𝜎2 = 𝑝𝑑 2𝑑
  • C. 𝜎1 = 𝑝𝑑 4𝑑; 𝜎2 = 𝑝𝑑 2𝑑
  • D. 𝜎1 = 𝑝𝑑 2𝑑; 𝜎2 = 0

Answer: A. 𝜎1 = 𝑝𝑑 2𝑑; 𝜎2 = 𝑝𝑑 4𝑑

Question 71

Type: MSQ | Marks: 1

A spring mass system is shown in the figure below. Take the acceleration due to gravity as 𝑔 = 9.81 m/s2. The static deflection due to weight and the time period of oscillations, respectively, are

Figure for question 71, GATE XE (Engineering Sciences) 2023

  • A. 0.392 m and 1.26 s
  • B. 0.392 m and 3.52 s
  • C. 0.626 m and 1.26 s
  • D. 0.626 m and 3.52 s

Answer: A. 0.392 m and 1.26 s

Question 72

Type: NAT | Marks: 1

A rod is subjected to three forces as shown in the figure on the left. An equivalent force system with forces F1, F2 and moment M is shown in the figure on the right. The value of M (in N-m) is______(rounded off to one decimal place).

Figure for question 72, GATE XE (Engineering Sciences) 2023

Answer: 117.0 to 118.0

Question 73

Type: NAT | Marks: 1

A simply supported beam of length 3 m is loaded as shown in the figure. The magnitude of the shear force (in kN) at the mid-point of the beam is______(rounded off to one decimal place).

Figure for question 73, GATE XE (Engineering Sciences) 2023

Answer: 4.9 to 5.1

Question 74

Type: NAT | Marks: 1

For a plane stress problem, the principal stresses are 100 MPa and 50 MPa. The magnitude of maximum shear stress (in MPa) in the material is______(rounded off to one decimal place).

Answer: 49.5 to 50.5

Question 75

Marks: 2

A solid uniform rigid disk of mass π‘š and radius 𝑅 rolls without slipping along a horizontal surface PQ. The speed of the center of the disk is 𝑣. The disk then strikes a hurdle of height 3𝑅 20 at point S. During the impact, there is no rebound or slip at S and no impulse from the surface PQ. The magnitude of the velocity of the center of the disk immediately after the impact is

Figure for question 75, GATE XE (Engineering Sciences) 2023

  • A. 0.1𝑣
  • B. 0.3𝑣
  • C. 0.7𝑣
  • D. 0.9𝑣

Answer: D. 0.9𝑣

Question 76

Marks: 2

A cylinder made of rubber (length = L and diameter = d) is inserted in a rigid container as shown in the figure. The rubber cylinder fits snugly in the rigid container. There is no wall friction. The modulus of elasticity of the rubber is E and its Poisson’s ratio is Ξ½. The cylinder is subjected to a small uniform pressure 𝑝 as shown in the figure. The resulting axial strain (πœ€π‘§π‘§) is

Figure for question 76, GATE XE (Engineering Sciences) 2023

  • A. βˆ’ 𝑝 𝐸
  • B. βˆ’ 𝑝 𝐸(1 βˆ’2Ξ½)
  • C. βˆ’ 𝑝 𝐸[(1 + Ξ½)(1 βˆ’2Ξ½) (1 βˆ’Ξ½) ]
  • D. βˆ’ 𝑝 𝐸[(1 βˆ’Ξ½)(1 βˆ’2Ξ½) (1 + Ξ½) ]

Answer: C. βˆ’ 𝑝 𝐸[(1 + Ξ½)(1 βˆ’2Ξ½) (1 βˆ’Ξ½) ]

Question 77

Marks: 2

The state of stress at the critical location in a structure is 𝜎π‘₯π‘₯ = 420 MPa, πœŽπ‘¦π‘¦ = 100 MPa, πœŽπ‘§π‘§= 𝜎π‘₯𝑦 = πœŽπ‘¦π‘§= πœŽπ‘§π‘₯= 0. The yield stress of the material in uniaxial tension is 400 MPa. Select the correct statement among the following.

  • A. The structure is safe by both Tresca (maximum shear stress) theory and von-Mises (distortion energy) theory.
  • B. The structure is safe by Tresca (maximum shear stress) theory and unsafe by von-Mises (distortion energy) theory.
  • C. The structure is unsafe by Tresca (maximum shear stress) theory and safe by von-Mises (distortion energy) theory.
  • D. The structure is unsafe by both Tresca (maximum shear stress) theory and von-Mises (distortion energy) theory.

Answer: C. The structure is unsafe by Tresca (maximum shear stress) theory and safe by von-Mises (distortion energy) theory.

Question 78

Marks: 2

The figure shows a column of rectangular cross section 100 mm Γ— 80 mm. It carries a load of 60 kN at a point 30 mm from the edge 𝑃𝑄. The values of stress component πœŽπ‘§π‘§ on surfaces 𝑃𝑄𝑄′𝑃′ and 𝑆𝑅𝑅′𝑆′, at points far away from both ends of the column, are respectively

Figure for question 78, GATE XE (Engineering Sciences) 2023

  • A. 18.75 N/mm2 (Compressive) and 3.75 N/mm2 (Tensile)
  • B. 18.75 N/mm2 (Compressive) and 3.75 N/mm2 (Compressive)
  • C. 13.13 N/mm2 (Compressive) and 1.88 N/mm2 (Tensile)
  • D. 13.13 N/mm2 (Compressive) and 1.88 N/mm2 (Compressive)

Answer: D. 13.13 N/mm2 (Compressive) and 1.88 N/mm2 (Compressive)

Question 79

Marks: 2

Consider an electric pole with dimensions as shown in the figure. Let the end R be subjected to a vertical force F. The flexural rigidity of both vertical and horizontal bars is EI. Neglect the axial deflection of the vertical bar, and all effects of self-weight. The vertical deflection at end R is

Figure for question 79, GATE XE (Engineering Sciences) 2023

  • A. 7𝐹𝐿3 3𝐸𝐼
  • B. 10𝐹𝐿3 3𝐸𝐼
  • C. 5𝐹𝐿3 3𝐸𝐼
  • D. 8𝐹𝐿3 3𝐸𝐼

Answer: A. 7𝐹𝐿3 3𝐸𝐼

Question 80

Type: MSQ | Marks: 2

A uniform cantilever beam has flexural rigidity 𝐸𝐼 and length 𝐿. It is subjected to a concentrated force 𝐹 and moment 𝑀= 2𝐹𝐿 at the free end as shown. The deflection (𝛿) at the free end is

Figure for question 80, GATE XE (Engineering Sciences) 2023

  • A. 11𝐹𝐿3 12𝐸𝐼
  • B. 8𝐹𝐿3 9𝐸𝐼
  • C. 4𝐹𝐿3 3𝐸𝐼
  • D. 7𝐹𝐿3 6𝐸𝐼

Answer: C. 4𝐹𝐿3 3𝐸𝐼

Question 81

Type: NAT | Marks: 2

A steel ball of mass π‘š = 10 kg is suspended from the ceiling of a moving carriage by two inextensible strings making 60Β° with the horizontal as shown. The carriage has an acceleration π‘Ž such that the tension in the string on the right is double the tension in the string on the left. Take the acceleration due to gravity (g) as 10 m/s2. The acceleration π‘Ž (in m/s2) is______(rounded off to one decimal place).

Figure for question 81, GATE XE (Engineering Sciences) 2023

Answer: 1.8 to 2.0

Question 82

Type: NAT | Marks: 2

A block of mass π‘š= 10 kg is lying on an inclined plane PQ. The mass is restrained from sliding down the inclined plane by a force 𝐹. The coefficient of friction between the block and the inclined plane is 0.3. Take the acceleration due to gravity as 10 m/s2. The smallest force 𝐹 (in N) required to prevent the block from sliding down is______(rounded off to one decimal place).

Figure for question 82, GATE XE (Engineering Sciences) 2023

Answer: 23.0 to 25.0

Question 83

Type: NAT | Marks: 2

A spherical rigid ball of mass 10 kg is moving with a speed of 2 m/s in the direction shown. The ball collides with a rigid frictionless wall and rebounds at an angle 𝛼 with a speed of 𝑣, as shown. The coefficient of restitution is 0.9. The angle 𝛼 (in degrees) is______(rounded off to one decimal place).

Figure for question 83, GATE XE (Engineering Sciences) 2023

Answer: 57.0 to 58.0

Question 84

Type: NAT | Marks: 2

A thin steel plate is loaded in the x-y plane as shown in the figure. Take the Poisson’s ratio of steel to be 0.3 and the modulus of elasticity of steel to be 200 GPa. The strain along the 𝑧-direction is πœ€π‘§π‘§= βˆ’3 Γ— 10βˆ’4. The value of πœŽπ‘¦π‘¦ (in MPa) is______(rounded off to one decimal place).

Figure for question 84, GATE XE (Engineering Sciences) 2023

Answer: 79.5 to 80.5

Question 85

Type: NAT | Marks: 2

A composite rod made of steel and copper is fixed immovably at its ends as shown in the figure. The length of each portion of the rod is 1 m as shown. The cross-sections of both portions are the same. The moduli of elasticity of steel and copper are 200 GPa and 100 GPa, respectively. The coefficients of thermal expansion of steel and copper are 12 Γ— 10βˆ’6 /℃ and 18 Γ— 10βˆ’6 /℃, respectively. The composite rod is initially stress free. Then, the temperature of the composite rod is increased by 100 ℃. The magnitude of axial stress (in MPa) developed in the steel rod is______(rounded off to one decimal place).

Figure for question 85, GATE XE (Engineering Sciences) 2023

Answer: 199.0 to 201.0

Question 86

Type: NAT | Marks: 2

A slender uniform elastic rod of length 1 m and of solid circular cross-section of diameter 50 mm is originally straight. It is then loaded by equal and opposite end moments as indicated in the figure. The resulting lateral displacement of the mid-point of the rod is 10 mm (displacements are exaggerated in the figure). The maximum longitudinal strain in the rod is 𝑝 Γ— 10βˆ’3, where 𝑝 is______(rounded off to one decimal place).

Figure for question 86, GATE XE (Engineering Sciences) 2023

Answer: 1.9 to 2.1

Question 87

Type: NAT | Marks: 2

Consider a solid cylindrical shaft and a hollow cylindrical shaft. Both shafts are axisymmetric and elastic, and have the same cross-sectional area. The hollow shaft has an outside diameter of 150 mm and an inside diameter of 120 mm. When both the shafts are twisted by the same twisting moment, the ratio of maximum shear stress developed in the hollow shaft (πœβ„Ž) to maximum shear stress developed in the solid shaft (πœπ‘ ) will be______(rounded off to three decimal places).

Answer: 0.350 to 0.380

Thermodynamics

Question 88

Marks: 1

A The number of properties required to fix the state of a system is given by β€˜state postulate’. R The state of a simple compressible system is completely specified by two independent, intensive properties. About the statements A and R applied to a single-phase system,

  • A. A is correct and R is incorrect.
  • B. A is incorrect and R is correct.
  • C. Both A and R are incorrect.
  • D. Both A and R are correct.

Answer: D. Both A and R are correct.

Question 89

Marks: 1

Which of the following is an extensive property of a system?

  • A. Density
  • B. Pressure
  • C. Temperature
  • D. Total mass

Answer: D. Total mass

Question 90

Marks: 1

A tank of volume V contains homogeneous mixture of two ideal gases, A and B at a temperature T and a pressure P. The mixture contains nA moles of gas A and nB moles of gas B. If PA and PB are the partial pressures of gas A and gas B, respectively, then

  • A. 𝑃𝐴= 𝑛𝐴 𝑛𝐴+ 𝑛𝐡 𝑃, 𝑃𝐡= 𝑛𝐡 𝑛𝐴+ 𝑛𝐡 𝑃
  • B. 𝑃𝐴= 𝑛𝐡 𝑛𝐴 𝑃, 𝑃𝐡= 𝑛𝐴 𝑛𝐡 𝑃
  • C. 𝑃𝐴= 𝑛𝐴 𝑛𝐡 𝑃, 𝑃𝐡= 𝑛𝐡 𝑛𝐴 𝑃
  • D. 𝑃𝐴= 𝑛𝐡 𝑛𝐴+ 𝑛𝐡 𝑃, 𝑃𝐡= 𝑛𝐴 𝑛𝐴+ 𝑛𝐡 𝑃

Answer: A. 𝑃𝐴= 𝑛𝐴 𝑛𝐴+ 𝑛𝐡 𝑃, 𝑃𝐡= 𝑛𝐡 𝑛𝐴+ 𝑛𝐡 𝑃

Question 91

Marks: 1

If an ideal air-standard Otto cycle and an ideal air-standard Diesel cycle operate on the same compression ratio, then the relation between the thermal efficiencies (Ξ·th) of the cycles is

  • A. πœ‚π‘‘β„Ž,π‘‚π‘‘π‘‘π‘œ= πœ‚π‘‘β„Ž,𝐷𝑖𝑒𝑠𝑒𝑙 and πœ‚π‘‘β„Ž,π‘‚π‘‘π‘‘π‘œ< 1
  • B. πœ‚π‘‘β„Ž,π‘‚π‘‘π‘‘π‘œ> πœ‚π‘‘β„Ž,𝐷𝑖𝑒𝑠𝑒𝑙
  • C. πœ‚π‘‘β„Ž,π‘‚π‘‘π‘‘π‘œ< πœ‚π‘‘β„Ž,𝐷𝑖𝑒𝑠𝑒𝑙
  • D. πœ‚π‘‘β„Ž,π‘‚π‘‘π‘‘π‘œ= πœ‚π‘‘β„Ž,𝐷𝑖𝑒𝑠𝑒𝑙= 1

Answer: B. πœ‚π‘‘β„Ž,π‘‚π‘‘π‘‘π‘œ> πœ‚π‘‘β„Ž,𝐷𝑖𝑒𝑠𝑒𝑙

Question 92

Marks: 1

The following statements are given: (i) The third law of thermodynamics deals with the entropy of a substance at the absolute zero temperature. (ii) Entropy of any non-crystalline structure is zero at absolute zero temperature. (iii) At the absolute zero temperature, the crystal structure has maximum degree of order. (iv) The thermal energy of the substance at absolute zero temperature is maximum. The correct option describing these statements is

  • A. Only (i) is correct
  • B. Only (ii) is correct
  • C. Both (i) and (iii) are correct
  • D. Both (i) and (iv) are correct

Answer: C. Both (i) and (iii) are correct

Question 93

Marks: 1

Adiabatic bulk modulus of a substance is defined as

  • A. βˆ’1 𝑣(πœ•π‘£ πœ•π‘ƒ) 𝑇
  • B. βˆ’π‘£(πœ•π‘ƒ πœ•π‘£) 𝑇
  • C. βˆ’1 𝑣(πœ•π‘£ πœ•π‘ƒ) 𝑠
  • D. βˆ’π‘£(πœ•π‘ƒ πœ•π‘£) 𝑠

Answer: D. βˆ’π‘£(πœ•π‘ƒ πœ•π‘£) 𝑠

Question 94

Type: NAT | Marks: 1

An insulated rigid closed tank of 2 m3 internal volume contains saturated liquid- vapor mixture of water at 200 ℃. The quality of the mixture is 0.75. The mass of the mixture in the tank is ____________ kg (rounded off to one decimal place). Use the following data for water: At 200 ℃: vf = 0.001156 m3/kg, vfg = 0.12620 m3/kg, vg = 0.12736 m3/kg

Answer: 20.5 to 21.5

Question 95

Type: NAT | Marks: 1

A rigid closed tank contains 2 kg of an ideal gas at 500 kPa and 350 K. A valve is opened, and half of the mass of the gas is allowed to escape. Then the valve is closed. If the final pressure in the tank is 300 kPa, the final temperature in the tank is ____________ K (in integer).

Answer: 420

Question 96

Type: NAT | Marks: 1

Air at 400 K and 200 kPa is heated at constant pressure to 600 K. Assuming that the internal energy is a function of temperature only, the magnitude of change in internal energy during this process is ____________ kJ/kmol (rounded off to one decimal place). Use the following data: Molar specific heat of air at constant volume: 𝑐̅𝑣 (kJ/kmol-K) = π‘Ž+ 𝑏𝑇+ 𝑐𝑇2 where 𝑇 is temperature in K, π‘Ž = 19.686 kJ/kmol-K, 𝑏 = 0.002 kJ/kmol-K2 and 𝑐= 0.5 Γ— 10βˆ’5 kJ/kmol-K3.

Answer: 4389 to 4392

Question 97

Marks: 2

A rigid closed tank having a volume of 2 m3 contains 0.1 m3 of saturated liquid water and 1.9 m3 of saturated water vapor at 100 kPa. Heat is transferred to the tank until the final tank pressure reaches 2 MPa. Following data for water is given: At 100 kPa: vf = 0.001043 m3/kg, vg = 1.694 m3/kg, uf = 417.33 kJ/kg, ug = 2506.06 kJ/kg At 2 MPa: vf = 0.001177 m3/kg, vg = 0.09963 m3/kg, uf = 906.42 kJ/kg, ug = 2600.26 kJ/kg The magnitude of heat transfer in this process is

  • A. 34670 kJ
  • B. 55842 kJ
  • C. 67906 kJ
  • D. 77470 kJ

Answer: D. 77470 kJ

Question 98

Marks: 2

An ideal Diesel cycle has a compression ratio of 20 and cut-off ratio of 1.5. At the beginning of the compression stroke, air is at 100 kPa, 300 K. Use the cold-air-standard assumptions with property value cp = 1.005 kJ/kg-K. Assume cp / cv = 1.4. For this cycle, the net work output per unit mass is

  • A. 335 kJ/kg
  • B. 395 kJ/kg
  • C. 500 kJ/kg
  • D. 165 kJ/kg

Answer: A. 335 kJ/kg

Question 99

Marks: 2

A 5 kg metal block (cp = 0.5 kJ/kg-K) at 373 K is submerged into 10 kg of water (cp = 4.2 kJ/kg-K) at 293 K in an insulated rigid container without spilling. Assuming thermal equilibrium is reached, the approximate entropy change of the universe is

  • A. βˆ’0.565 kJ/K
  • B. 0.073 kJ/K
  • C. 0.642 kJ/K
  • D. 0.963 kJ/K

Answer: B. 0.073 kJ/K

Question 100

Marks: 2

Match the following: Thermodynamic function/equation Expression A1 Helmholtz function (a) B1 ( d d𝑇(ln 𝑃)) π‘ π‘Žπ‘‘ = β„Žπ‘”βˆ’β„Žπ‘“ 𝑅𝑇2 A2 Gibbs function (g) B2 π‘’βˆ’π‘‡π‘  A3 T-ds equation B3 d𝑒= 𝑇dπ‘ βˆ’π‘ƒd𝑣 A4 Clapeyron-Clausius equation B4 β„Žβˆ’π‘‡π‘  .

  • A. A1β†’B2, A2β†’B4, A3β†’B1, A4β†’B3
  • B. A1β†’B4, A2β†’B2, A3β†’B1, A4β†’B3
  • C. A1β†’B2, A2β†’B4, A3β†’B3, A4β†’B1
  • D. A1β†’B4, A2β†’B2, A3β†’B3, A4β†’B1

Answer: C. A1β†’B2, A2β†’B4, A3β†’B3, A4β†’B1

Question 101

Type: NAT | Marks: 2

A piston-cylinder device initially contains 1 m3 of air at 200 kPa and 25 ℃. Air expands at constant pressure while a heater of 250 W is switched on for 10 minutes. There is a heat loss of 4 kJ during this process. Assuming air as an ideal gas, the final temperature of air is ____________ ℃ (rounded off to one decimal place). Use the following data for air: R = 0.287 kJ/kg-K, cp = 1.005 kJ/kg-K

Answer: 85.0 to 88.0

Question 102

Type: NAT | Marks: 2

Steam at 2 MPa and 300 ℃ steadily enters a nozzle of inlet diameter of 20 cm. Steam leaves the nozzle with a velocity of 300 m/s. The mass flow rate of steam through the nozzle is 10 kg/s. Assume no work interaction and no change in potential energy. If the heat loss from the nozzle per kg of steam is 3 kJ, the exit enthalpy per kg of steam is ____________ kJ (rounded off to nearest integer). Use the following data for steam: At 2 MPa and 300 ℃: v = 0.12551 m3/kg, h = 3024.2 kJ/kg

Answer: 2975 to 2980

Question 103

Type: NAT | Marks: 2

A rigid tank of 2 m3 internal volume contains 5 kg of water as a saturated liquid-vapor mixture at 400 kPa. Half of the mass of the saturated liquid in the tank is drained-off while maintaining constant pressure of 400 kPa in the tank. The final quality of the mixture remaining in the tank is ____________ (rounded off to two decimal places). Use the following data for water: At 400 kPa: vf = 0.001084 m3/kg, vfg = 0.46138 m3/kg, vg = 0.46246 m3/kg

Answer: 0.90 to 0.95

Question 104

Type: NAT | Marks: 2

Consider a spark ignition engine which operates on an ideal air-standard Otto cycle. It uses a fuel which produces 44 MJ/kg of heat in the engine. If the engine requires 40 mg of fuel to produce 1 kJ of work output, then the compression ratio of the Otto cycle is ____________ (rounded off to two decimal places). For the entire cycle, use cp / cv = 1.4

Answer: 8.00 to 8.30

Question 105

Type: NAT | Marks: 2

A refrigerator operates on an ideal vapor compression cycle between the pressure limits of 140 kPa and 800 kPa. The working fluid is the refrigerant R-134a. The refrigerant enters the compressor as saturated vapor at 140 kPa and exits at 800 kPa and 60 ℃. It leaves the condenser as a saturated liquid at 800 kPa. The coefficient of performance (COP) of the refrigerator is ____________ (rounded off to two decimal places). Use the following property data for R-134a: At 140 kPa: hf = 27.06 kJ/kg, hg = 239.19 kJ/kg At 800 kPa: hf = 95.48 kJ/kg, hg = 267.34 kJ/kg At 800 kPa and 60 ℃: h = 296.82 kJ/kg

Answer: 2.45 to 2.55

Question 106

Type: NAT | Marks: 2

A steam power plant operates on a simple ideal Rankine cycle. The condenser pressure is 10 kPa and the boiler pressure is 5 MPa. The steam enters the turbine at 600 ℃. Mass flow rate of the steam is 50 kg/s. Neglecting the pump work, the net power output of the plant is ____________ MW (rounded off to one decimal place). Use the following property data for water: At 10 kPa: hf = 191.81 kJ/kg, hfg = 2392.82 kJ/kg, hg = 2584.63 kJ/kg sf = 0.6492 kJ/kg-K, sfg = 7.5010 kJ/kg-K, sg = 8.1502 kJ/kg-K At 5 MPa and 600 ℃: h = 3666.47 kJ/kg, s = 7.2588 kJ/kg-K

Answer: 67.3 to 69.3

Question 107

Type: NAT | Marks: 2

In an air-conditioning system, air enters at 20 ℃ and 30% relative humidity at a steady rate of 30 m3/min in a humidifier and it is conditioned to 25 ℃ and 60% relative humidity. Assuming entire process takes place at pressure of 100 kPa, the mass flow rate of the steam added to air in the humidifier is ____________ kg/min (rounded off to three decimal places). Use the following property data: At 20 ℃ and 25 ℃, saturation pressures of water are 2.3392 kPa and 3.1698 kPa, respectively. For air, R = 0.287 kJ/kg-K

Answer: 0.262 to 0.290

Question 108

Type: NAT | Marks: 2

An office uses a heat pump to receive 500 kJ/day heat in winter to maintain its temperature at 300 K. The ambient temperature is 280 K. If the COP of the heat pump is 60% of its theoretical maximum value, the ratio of actual work input to the minimum theoretical work input to the heat pump is ____________ (rounded off to one decimal place).

Answer: 1.6 to 1.8

Question 109

Type: NAT | Marks: 2

In a liquid-vapour phase change process, ( d𝑃 d𝑇) π‘ π‘Žπ‘‘at 100 Β°C for saturated water is 3750 Pa/K. If the resulting change in specific volume (π‘£π‘”βˆ’π‘£π‘“) is 1.672 m3/kg, the enthalpy of vaporization (β„Žπ‘“π‘”) will be ____________ kJ/kg (in integer).

Answer: 2337 to 2341