The GATE 2025 MT Question paper with Solution PDF is available to download here. GATE 2025 was conducted by IIT Roorkee. The exam consists of 65 questions carrying a total of 100 marks, with 10 from the General Aptitude section and 55 questions from Engineering Mathematics and Core Metallurgical Engineering topics.

The difficulty level of GATE 2025 MT was moderate.

GATE 2025 MT Question Paper with Solutions PDF

GATE 2025 MT Question Paper with Answer Key Download PDF Check Solutions
GATE 2025 MT Question Paper with Solution Answer Key PDF

GATE 2025 MT Question Paper with Solutions

Question 1:

Despite his initial hesitation, Rehman's _______ to contribute to the success of the project never wavered.
Select the most appropriate option to complete the above sentence.

  • (A) ambivalence
  • (B) satisfaction
  • (C) resolve
  • (D) revolve

Question 2:

Bird : Nest :: Bee : ?

Select the correct option to complete the analogy.

  • (A) Kennel
  • (B) Hammock
  • (C) Hive
  • (D) Lair

Question 3:

If \(Pe^x = Qe^{-x}\) for all real values of \(x\), which one of the following statements is true?

  • (A) \(P = Q = 0\)
  • (B) \(P = Q = 1\)
  • (C) \(P = 1; Q = -1\)
  • (D) \(\frac{P}{Q} = 0\)

Question 4:

The paper as shown in the figure is folded to make a cube where each square corresponds to a particular face of the cube. Which one of the following options correctly represents the cube?




Question 5:

Let \(p_1\) and \(p_2\) denote two arbitrary prime numbers. Which one of the following statements is correct for all values of \(p_1\) and \(p_2\)?

  • (A) \(p_1 + p_2\) is not a prime number.
  • (B) \(p_1 p_2\) is not a prime number.
  • (C) \(p_1 + p_2 + 1\) is a prime number.
  • (D) \(p_1 p_2 + 1\) is a prime number.

Question 6:

Based on the conversation below, identify the logically correct inference:
"Even if I had known that you were in the hospital, I would not have gone there to see you," Ramya told Josephine.

  • (A) Ramya knew that Josephine was in the hospital.
  • (B) Ramya did not know that Josephine was in the hospital.
  • (C) Ramya and Josephine were once close friends; but now, they are not.
  • (D) Josephine was in the hospital due to an injury to her leg.

Question 7:

Select the correct option to complete the analogy.
Komal : Fresh :: Five : ?

  • (A) Ten
  • (B) Six
  • (C) Three
  • (D) Four

Question 8:

Which one of the following options is correct for the given data in the table?


  • (A) \(X(i) = X(i - 1) + I(i)\); \(Y(i) = Y(i - 1) I(i)\); \(i > 0\)
  • (B) \(X(i) = X(i - 1) I(i)\); \(Y(i) = Y(i - 1) + I(i)\); \(i > 0\)
  • (C) \(X(i) = X(i - 1) I(i)\); \(Y(i) = Y(i - 1) I(i)\); \(i > 0\)
  • (D) \(X(i) = X(i - 1) + I(i)\); \(Y(i) = Y(i - 1) + I(i - 1)\); \(i > 0\)

Question 9:

In the given figure, PQRS is a square of side 2 cm and PLMN is a rectangle. The corner L of the rectangle is on the side QR. Side MN of the rectangle passes through the corner S of the square. What is the area (in cm\(^2\)) of the rectangle PLMN?

  • (A) \(2\sqrt{2}\)
  • (B) 2
  • (C) 8
  • (D) 4

Question 10:

The diagram below shows a river system consisting of 7 segments, marked P, Q, R, S, T, U, and V. It splits the land into 5 zones, marked Z1, Z2, Z3, Z4, and Z5. We need to connect these zones using the least number of bridges. Out of the following options, which one is correct?

  • (A) Bridges on P, Q, and T
  • (B) Bridges on P, Q, S, and T
  • (C) Bridges on Q, S, and V
  • (D) Bridges on P, Q, S, U, and V

Question 11:

Which one of the following matrices has eigenvalues 1 and 6?

  • (A) \(\begin{bmatrix} 5 & -2
    -2 & 2 \end{bmatrix}\)
  • (B) \(\begin{bmatrix} 3 & -1
    -2 & 2 \end{bmatrix}\)
  • (C) \(\begin{bmatrix} 3 & -1
    -1 & 2 \end{bmatrix}\)
  • (D) \(\begin{bmatrix} 2 & -1
    -1 & 3 \end{bmatrix}\)

Question 12:

For an isobaric process, the heat transferred is equal to the change in __________ of the system.

  • (A) enthalpy
  • (B) entropy
  • (C) Helmholtz free energy
  • (D) Gibbs free energy

Question 13:

Match each crystal defect in \textbf{Column I} with the corresponding type in \textbf{Column II}.


\begin{tabular{p{0.45\linewidth p{0.45\linewidth
Column I & Column II

P. Edge dislocation & 1. Zero-dimensional defect

Q. Stacking fault & 2. One-dimensional defect

R. Frenkel defect & 3. Two-dimensional defect

S. Porosity & 4. Three-dimensional defect

\end{tabular

  • (A) P -- 3, Q -- 4, R -- 2, S -- 1
  • (B) P -- 3, Q -- 4, R -- 1, S -- 2
  • (C) P -- 2, Q -- 3, R -- 1, S -- 4
  • (D) P -- 2, Q -- 4, R -- 3, S -- 1

Question 14:

At high temperatures, which one of the following empirical expressions correctly describes the variation of dynamic viscosity \(\mu\) of a Newtonian liquid with absolute temperature \(T\)?

\textit{Given: \(A\) and \(B\) are positive constants.

  • (A) \(\mu = A + BT\)
  • (B) \(\mu = A \exp\!\left(-\dfrac{B}{T}\right)\)
  • (C) \(\mu = A \exp(BT)\)
  • (D) \(\mu = A \exp\!\left(\dfrac{B}{T}\right)\)

Question 15:

Which one of the following is an intensive property?

  • (A) Chemical potential
  • (B) Volume
  • (C) Mass
  • (D) Entropy

Question 16:

Hot metal from a blast furnace is treated with mill scale prior to oxygen steelmaking for _____.

  • (A) dephosphorization
  • (B) decarburization
  • (C) desulphurization
  • (D) desiliconization

Question 17:

In optical microscopy, which one of the following combinations of wavelength (\(\lambda\)) and numerical aperture (NA) provides the best spatial resolution?

  • (A) \(\lambda = 400 \, nm, \; NA = 1.0\)
  • (B) \(\lambda = 600 \, nm, \; NA = 1.2\)
  • (C) \(\lambda = 400 \, nm, \; NA = 1.2\)
  • (D) \(\lambda = 600 \, nm, \; NA = 1.0\)

Question 18:

The coordination number for an octahedral site in pure copper is ____.

  • (A) 4
  • (B) 6
  • (C) 8
  • (D) 12

Question 19:

Consider the following gas-phase reaction: \[ 2SO_2 + O_2 \;\;\rightleftharpoons\;\; 2SO_3 \]
If the enthalpy of reaction is negative, which one of the following conditions promotes a higher equilibrium concentration of SO\(_3\)?

  • (A) Higher pressure and higher temperature
  • (B) Higher pressure and lower temperature
  • (C) Lower pressure and higher temperature
  • (D) Lower pressure and lower temperature

Question 20:

Which one of the following slag components is responsible for the oxidizing power of steelmaking slags?

  • (A) SiO\(_2\)
  • (B) CaO
  • (C) MgO
  • (D) FeO

Question 21:

Two randomly oriented polycrystalline copper samples with average grain sizes of 10\,\(\mu\)m (Sample A) and 100\,\(\mu\)m (Sample B) were tested at room temperature.

Given: \(E_A=\) Young’s modulus of Sample A, \(E_B=\) Young’s modulus of Sample B, \(\mathrm{YS}_A=\) Yield strength of Sample A, \(\mathrm{YS}_B=\) Yield strength of Sample B.
Which one of the following statements is CORRECT?

  • (A) \; \(E_A>E_B\) and \(\mathrm{YS}_A>\mathrm{YS}_B\)
  • (B) \; \(E_A=E_B\) and \(\mathrm{YS}_A<\mathrm{YS}_B\)
  • (C) \; \(E_A>E_B\) and \(\mathrm{YS}_A=\mathrm{YS}_B\)
  • (D) \; \(E_A=E_B\) and \(\mathrm{YS}_A>\mathrm{YS}_B\)

Question 22:

In metal casting, which one of the following gating ratios (sprue : runner : gate area ratio) represents a non-pressurized gating system?

  • (A) 1 : 2 : 3
  • (B) 3 : 2 : 1
  • (C) 4 : 3 : 1
  • (D) 5 : 4 : 1

Question 23:

In the Fe–C system, the invariant reaction Liquid + \(\delta\) \(\;\rightleftharpoons\;\) \(\gamma\) takes place at 1493\(^\circ\)C. This type of reaction is called ____.

  • (A) eutectic
  • (B) eutectoid
  • (C) peritectic
  • (D) monotectic

Question 24:

Match the following elements in Column I with their respective ores in Column II.

\begin{tabular{ll
Column I & Column II

P. Al & 1. Rutile

Q. Fe & 2. Hematite

R. Ti & 3. Chalcopyrite

S. Cu & 4. Bauxite

\end{tabular

  • (A) P – 4, Q – 2, R – 3, S – 1
  • (B) P – 2, Q – 4, R – 1, S – 3
  • (C) P – 3, Q – 1, R – 4, S – 2
  • (D) P – 4, Q – 2, R – 1, S – 3

Question 25:

Which of the following functions is/are expandable using Maclaurin series?

  • (A) \(\ln(1+z)\)
  • (B) \(\ln z\)
  • (C) \(\dfrac{1}{z^2}\)
  • (D) \(\exp(z)\)

Question 26:

With reference to edge and screw dislocations, which of the following statements is/are CORRECT?

  • (A) Both edge and screw dislocations can leave the slip plane by climb.
  • (B) Burgers vector of a screw dislocation is parallel to its line vector.
  • (C) Both edge and screw dislocations can leave the slip plane by cross-slip.
  • (D) Strain energy per unit length of an edge dislocation is higher than that of a screw dislocation.

Question 27:

Which of the following conditions is/are favorable for producing low-silicon hot metal in blast furnace ironmaking?

  • (A) Reduced raceway adiabatic flame temperature
  • (B) Oxygen-enriched blast
  • (C) Lime injection through tuyeres
  • (D) Increased hearth temperature

Question 28:

Which of the following statements is/are CORRECT with respect to the initial stage of GP zone formation in a precipitation-hardenable Al–4.5 wt.% Cu alloy?

  • (A) GP zones are Cu-rich clusters.
  • (B) GP zones are CuAl\(_2\) precipitates.
  • (C) GP zones are incoherent with the matrix.
  • (D) GP zones are coherent with the matrix.

Question 29:

Which of the following techniques can be used to detect an internal defect in a metal casting?

  • (A) Ultrasonic inspection
  • (B) Liquid (or dye) penetrant inspection
  • (C) Gamma-ray radiography
  • (D) X-ray radiography

Question 30:

Standard Gibbs free energies of formation of some solid oxides per mole of O\(_2\) at 1000 K are given below:

SiO\(_2\): \(-728\) kJ, \;\; TiO\(_2\): \(-737\) kJ, \;\; VO: \(-712\) kJ, \;\; MnO: \(-624\) kJ.

Regarding thermodynamic feasibility of oxide reduction, which statement(s) is/are CORRECT under standard conditions at 1000 K?

  • (A) Si can reduce TiO\(_2\).
  • (B) Mn can reduce VO.
  • (C) Ti can reduce MnO.
  • (D) V can reduce SiO\(_2\).

Question 31:

Consider a fully developed, steady, one-dimensional, laminar flow of a Newtonian liquid through a pipe. The maximum velocity in the pipe is proportional to which of the following quantities?

Given: \(\Delta P\) is the pressure drop, \(\mu\) is dynamic viscosity, \(R\) and \(L\) are the pipe radius and length.

  • (A) \(\Delta P\)
  • (B) \(1/R^{2}\)
  • (C) \(1/\mu\)
  • (D) \(1/L\)

Question 32:

The hydrostatic stress for the stress tensor provided below is _____ MPa (in integer). \[ \begin{bmatrix} 150 & 0 & 0
0 & -100 & 100
0 & 100 & 250 \end{bmatrix}\ MPa \]


Question 33:

Re is kept constant. A liquid with \(\rho_1=1\ g cm^{-3}\), \(\mu_1=0.01\) Poise flows at \(v_1=1\ cm s^{-1}\). If replaced with \(\rho_2=1.25\ g cm^{-3}\), \(\mu_2=0.015\) Poise (same length scale), the characteristic velocity will be _____ cm s\(^{-1}\) (rounded to one decimal place).


Question 34:

Consider the gas phase reaction: \( \mathrm{CO}+\tfrac{1}{2}\mathrm{O}_2 \rightleftharpoons \mathrm{CO}_2 \).
At equilibrium: \(P_{\mathrm{CO}}=10^{-6}\) atm, \(P_{\mathrm{O_2}}=10^{-6}\) atm, \(P_{\mathrm{CO_2}}=16\) atm.
The equilibrium constant for the reaction is _____ \(\times 10^{10}\) (rounded to one decimal place).


Question 35:

A linear regression model was fitted to a set of \((x,y)\) data. The total sum of squares and sum of squares of error are 1200 and 120, respectively. The coefficient of determination \((R^2)\) of the fit is _____ (rounded off to one decimal place).


Question 36:

For two continuous functions \(M(x,y)\) and \(N(x,y)\), the relation \(M \, dx + N \, dy = 0\) describes an exact differential equation if

  • (A) \(\dfrac{\partial M}{\partial x} = \dfrac{\partial N}{\partial y}\)
  • (B) \(\dfrac{\partial M}{\partial x} = -\dfrac{\partial N}{\partial y}\)
  • (C) \(\dfrac{\partial M}{\partial y} = \dfrac{\partial N}{\partial x}\)
  • (D) \(\dfrac{\partial M}{\partial y} = -\dfrac{\partial N}{\partial x}\)

Question 37:

Consider the phase diagram of a one-component system. \(V_\alpha, V_\beta,\) and \(V_{liquid}\) are the molar volumes of \(\alpha, \beta,\) and liquid phases, respectively.
Which one of the following statements is TRUE?
Given: The change in molar enthalpies, \(\Delta H^{\alpha \to \beta}\) and \(\Delta H^{\beta \to Liquid}\), are positive.

  • (A) \(V_\alpha < V_\beta \ and \ V_\beta < V_{Liquid}\)
  • (B) \(V_\alpha > V_\beta \ and \ V_\beta < V_{Liquid}\)
  • (C) \(V_\alpha < V_\beta \ and \ V_\beta > V_{Liquid}\)
  • (D) \(V_\alpha > V_\beta \ and \ V_\beta > V_{Liquid}\)
  • (A) P – 1, Q – 4, R – 2, S – 3
  • (B) P – 1, Q – 4, R – 3, S – 2
  • (C) P – 2, Q – 4, R – 1, S – 3
  • (D) P – 1, Q – 3, R – 2, S – 4
  • (A) \((T_s + T_\infty)^2 (T_s - T_\infty)\)
  • (B) \((T_s^2 + T_\infty^2)(T_s + T_\infty)\)
  • (C) \((T_s^2 - T_\infty^2)(T_s + T_\infty)\)
  • (D) \((T_s - T_\infty)^2 (T_s + T_\infty)\)
  • (A) P – 4, Q – 1, R – 2, S – 3
  • (B) P – 4, Q – 3, R – 2, S – 1
  • (C) P – 3, Q – 4, R – 2, S – 1
  • (D) P – 1, Q – 4, R – 2, S – 3
  • (A) \(\begin{bmatrix} \tfrac{1}{2} & -\tfrac{\sqrt{3}}{2}
    -\tfrac{\sqrt{3}}{2} & \tfrac{1}{2} \end{bmatrix}\)
  • (B) \(\begin{bmatrix} \tfrac{1}{2} & -\tfrac{\sqrt{3}}{2}
    \tfrac{\sqrt{3}}{2} & \tfrac{1}{2} \end{bmatrix}\)
  • (C) \(\begin{bmatrix} \tfrac{1}{\sqrt{2}} & -\tfrac{\sqrt{3}}{2}
    -\tfrac{\sqrt{3}}{2} & \tfrac{1}{2} \end{bmatrix}\)
  • (D) \(\begin{bmatrix} \tfrac{1}{\sqrt{2}} & -\tfrac{\sqrt{3}}{2}
    \tfrac{\sqrt{3}}{2} & -\tfrac{1}{\sqrt{2}} \end{bmatrix}\)

Question 38:

Match the casting defects in Column I with the characteristic features in Column II.


Column I \hspace{3cm Column II

P. Misrun \hspace{2.8cm 1. Penetration of liquid metal behind surface layer of sand moulds

Q. Expansion scab \hspace{1.3cm 2. Metal solidifies prematurely in the mould and some sections of the casting are not filled

R. Pin holes \hspace{2.7cm 3. Cracking because of restraint to contraction in certain areas of the casting during solidification and cooling to room temperature

S. Hot tearing \hspace{2.5cm 4. Evolution of gases during solidification resulting in porosity

  • (A) P – 2, Q – 4, R – 3, S – 1
  • (B) P – 1, Q – 3, R – 2, S – 4
  • (C) P – 1, Q – 2, R – 4, S – 3
  • (D) P – 2, Q – 1, R – 4, S – 3

Question 39:

The following are the activation energies for diffusion of carbon and iron at 773 K in polycrystalline BCC iron:

P = Activation energy for diffusion of carbon in BCC iron through the lattice

Q = Activation energy for diffusion of iron in BCC iron through the lattice

R = Activation energy for diffusion of iron in BCC iron along the grain boundary


Which one of the following statements is CORRECT?

  • (A) R \(<\) P \(<\) Q
  • (B) R \(<\) Q \(<\) P
  • (C) Q \(<\) P \(<\) R
  • (D) P \(<\) R \(<\) Q

Question 40:

Front tension is applied during cold rolling of a thin metal sheet. Which of the following statements is/are TRUE?

  • (A) The neutral point shifts towards the roll entrance.
  • (B) The rolling load is decreased.
  • (C) The neutral point shifts towards the roll exit.
  • (D) The rolling load is increased.

Question 41:

Which of the following statements is/are CORRECT when Ni is added as an alloying element to a low alloy steel?

  • (A) Hardenability is increased AND the \(M_s\) temperature is lowered.
  • (B) Hardenability is decreased AND the \(M_s\) temperature is lowered.
  • (C) Hardenability is increased AND the \(M_s\) temperature is raised.
  • (D) Hardenability is decreased AND the \(M_s\) temperature is raised.

Question 42:

Which of the following statements is/are CORRECT with respect to fusion welding and solid-state welding of metals and alloys?

  • (A) Thermomechanically affected zone is found in the fusion welding of pure metals.
  • (B) Partially melted zone is NOT found in the fusion welding of pure metal.
  • (C) Diffusion bonding is one type of solid-state welding process.
  • (D) Partially melted zone is found in the fusion welding of alloys with a large freezing range.

Question 43:

Which of the following welding processes does NOT / do NOT utilize consumable electrode?

  • (A) Plasma arc welding
  • (B) Gas metal arc welding
  • (C) Shielded metal arc welding
  • (D) Electron beam welding

Question 44:

For a two-dimensional field described by \(T(x,y)=\frac{1}{3}xy(x+y)\), the magnitude of its gradient at the point \((1,1)\) is ____ (rounded off to two decimal places).


Question 45:

X-ray diffraction with wavelength \(0.154\,nm\) gives the first peak at Bragg angle \(\theta=20^\circ\) for both a metal A (FCC) and a metal B (BCC). The value of \(\dfrac{lattice parameter of metal A}{lattice parameter of metal B}\) is ____ (rounded off to two decimal places).


Question 46:

The excess molar Gibbs free energy of a solution of elements A and B at \(1000~K\) is given by \(G^{XS}=-3000\,x_Ax_B~J mol^{-1}\). The activity of B in a solution containing \(40\) mol% of B at \(1000~K\) is ____ (rounded off to two decimal places).

Given: \(R=8.314~J mol^{-1}K^{-1}\).


Question 47:

Molten steel at \(1900~K\) is to be vacuum degassed. What equilibrium partial pressure of hydrogen is required to achieve \(1\) ppm (mass basis) of dissolved hydrogen? (rounded to two decimal places)

Given for \(\tfrac{1}{2}H_2(g)=[H]\): \(\log_{10}K_{\!eq}=-\dfrac{1900}{T}+2.4\) (with \(K_{\!eq}\) in ppm/\(\sqrt{atm}\)); \(1~atm=760~Torr\).


Question 48:

The value of \(\displaystyle \lim_{x\to 0}\frac{6(x-\sin x)}{x^3}\) is ____ (in integer).


Question 49:

For the reactions (in J):
\(Fe(s)+\tfrac{1}{2}O_2(g)\rightleftharpoons FeO(s)\), \(\Delta G^\circ=-264900+65T\)
\(2H_2(g)+O_2(g)\rightleftharpoons 2H_2O(g)\), \(\Delta G^\circ=-492900+109T\)

Assuming pure solids and no gas solubility, find at \(T=1000\,K\) the value of \(p_{H_2O}/p_{H_2}\) required to reduce FeO to Fe (rounded to two decimals).
Given \(R=8.314~J mol^{-1}K^{-1}\).


Question 50:

The diameter of spherical galena particles that have the same settling velocity as spherical quartz particles of diameter \(25\,\mum\) (both settling in water) is ____ \(\mum\) (rounded off to one decimal place).

Assume Stokes’ law is valid.

Given: \(\rho_{galena}=7400\ kg m^{-3}\), \(\rho_{quartz}=2600\ kg m^{-3}\), \(\rho_{water}=1000\ kg m^{-3}\).


Question 51:

Consider the cell reaction: \(\mathrm{Mg} + \mathrm{Cd}^{2+} \rightarrow \mathrm{Mg}^{2+} + \mathrm{Cd}\). The standard Gibbs free energy change for the reaction is ____ kJ (rounded off to an integer).

Given oxidation potentials (vs SHE): \(\mathrm{Mg} \rightleftharpoons \mathrm{Mg}^{2+} + 2e^- \; E^\circ = 2.37~V\), \(\mathrm{Cd} \rightleftharpoons \mathrm{Cd}^{2+} + 2e^- \; E^\circ = 0.403~V\).
Faraday’s constant \(F=96500~C mol^{-1}\).


Question 52:

Copper is electrodeposited from \(\mathrm{CuSO_4}\) onto a stainless-steel cathode of total surface area \(2~m^2\) in an electrolytic cell at current density \(200~A m^{-2}\) with current efficiency \(90%\). The mass of copper deposited in \(24~h\) is ____ kg (rounded off to two decimal places).

Given: \(F=96500~C mol^{-1}\), atomic mass of Cu \(=63.5~g mol^{-1}\). Reaction: \(\mathrm{Cu^{2+}+2e^-\rightarrow Cu}\) (\(n=2\)).


Question 53:

An intrinsic semiconductor has conductivity of \(100~\Omega^{-1}\,m^{-1}\) at \(300~K\) and \(300~\Omega^{-1}\,m^{-1}\) at \(500~K\). The band gap of the semiconductor is ____ eV (rounded off to two decimal places).

Given: \(k_B = 8.6\times10^{-5}\,eV K^{-1}\).


Question 54:

A component from alloy A with plane-strain toughness \(K_{IC}=50~MPa\sqrt{m}\) fractured at a crack length \(a=0.4\,mm\) under tensile stress \(\sigma\). If the same component is made from alloy B with \(K_{IC}=75~MPa\sqrt{m}\), the crack length at which fracture occurs (same \(\sigma\), same geometry) is ____ mm (rounded to one decimal place).


Question 55:

Temperatures at two sides of a \(0.4~m\) thick copper plate are \(1000^\circC\) and \(500^\circC\). Assuming steady, one-dimensional conduction with no end effects, the heat flux through the wall is \(\_\_\_\_\times 10^{5}\ W m^{-2}\) (in integer).

Given: \(k_{Cu}=400~W m^{-1}K^{-1}\).


Question 56:

In polycrystalline Ni, Nabarro–Herring diffusion creep controls the rate at a given temperature. If \(\dot\varepsilon=10^{-8}\ s^{-1}\) at \(\sigma=10\ MPa\), what stress gives \(\dot\varepsilon=10^{-9}\ s^{-1}\) (in integer MPa)? Assume the same mechanism remains rate-controlling.


Question 57:

A single crystal BCC metal with lattice parameter \(a=0.4~nm\) is deformed at a shear strain rate of \(0.001~s^{-1}\). If the average mobile dislocation density is \(10^{10}~m^{-2}\), the average dislocation velocity is \(\_\_\_\_\times 10^{-3}\ m s^{-1}\) (rounded off to two decimal places).

Given: Burgers vector \(\mathbf{b}=\dfrac{a}{2}\langle 111\rangle\).


Question 58:

A cylindrical specimen is plastically tensioned to a \emph{uniform elongation} of \(10%\). The final gage-section area is \(20~mm^2\). The initial gage-section area is ____ mm\(^2\) (rounded off to an integer).


Question 59:

The reaction \(A\rightarrow B\) follows first-order kinetics. At a given temperature, \(20%\) completion takes \(223~s\). The time to reach \(50%\) completion at the same temperature is ____ s (rounded to the nearest integer).


Question 60:

A cylindrical Al alloy billet of \(300~mm\) diameter is hot extruded to produce a cylindrical rod of \(75~mm\) diameter at a constant true strain rate \((\dot\varepsilon)\) of \(10~s^{-1}\). The flow stress at the extrusion temperature is \(\sigma=10(\dot\varepsilon)^{0.3}\) MPa.
Assume the alloy is perfectly plastic and there is no temperature rise during extrusion.
The ideal plastic work of deformation per unit volume is \(\_\_\_\_\times10^{6}~J m^{-3}\) (rounded to one decimal place).


Question 61:

Two consecutive Newton–Raphson estimates of the root of \(f(x)\) are \(x_i=8.5\) and \(x_{i+1}=13.5\). If \(f(x_i)=15\), the numerical value of \(f'(x_i)\) is ____ (in integer).