heegyu/mascqa · Datasets at Hugging Face

qids stringlengths 11 16	qstr stringclasses 4 values	num_words int64 9 145	questions stringlengths 44 799	subject stringclasses 14 values	label stringlengths 1 30	__index_level_0__ int64 0 113
G-META-22-40	MATCH	136	Find the correct match between dislocation reactions (Column A) to the descriptions (Column B) Column A: [(P) $a_°$/2 [-1 -1 1] + $a_°$/2 [1 1 1] = $a_°$ [ 0 0 1], (Q) $a_°$/6 [-1 2 -1 ] + $a_°$/6 [1 -1 2] = $a_°$/6 [0 1 1], (R) $a_°$/6 [1 -2 1] + $a_°$/6[-1 -1 2] = $a_°$/2 [0 -1 1] ] Column B: [(1) Leading partials merging to form a Lomer-cottrell lock in an FCC metal, (2) Energetically unfavorable dislocation reaction in an FCC metal, (3) Typical dislocation reaction in a BCC metal] Options: (A) P - 3, Q - 2, R - 1 (B) P - 3, Q - 1, R - 2 (C) P - 2, Q - 3, R - 1 (D) P - 2, Q - 1, R - 3	Atomic structure	B	86
G-META-22-41	MCQS	115	Match the phenomena (Column I) with the descriptions (Column II) Column I: [(P) Cottrell atmosphere, (Q) Suzuki interaction, (R) Bauschinger effect, (S) Nabarro- Herring creep] Column II: [(1) Decrease in yield stress when loading direction is reversed, (2) Stress assisted diffusion of vacancies resulting in plastic deformation in a polycrystalline material, (3) Lüders bands, (4) Segregation of solutes to the stacking fault] Options: (A) P - 1, Q - 2, R - 3, S - 4 (B) P - 1, Q - 2, R - 4, S - 3 (C) P - 3, Q - 4, R - 1, S - 2 (D) P - 3, Q - 1, R - 4, S - 2	Atomic structure	C	87
G-META-14-31	MCQS	54	Dissociation of a dislocation into two partials in an FCC metal is given by the following equation. (a/2)[1 -1 0] → (a/6)[2 -1 1] + (a/6)[1 -2 -1] . On which plane do these two partial dislocaitons lie? (A) (-1 1 1) (B) (1 1 1) (C) (1 -1 1) (D) (1 1 -1)	Atomic structure	D	88
G-META-16-12	NUM	22	The lattice parameter of face-centered cubic iron (γ-Fe) is 0.3571 nm. The radius (in nm) of the octahedral void in γ-Fe is?	Atomic structure	0.045 TO 0.06	89
G-META-17-19	NUM	40	Given: $λ_(CuKα)$ = 0.154 nm; lattice parameter of the metal = 0.36 nm. The second peak in the powder X-ray diffraction pattern of a FCC metal occurs at what Bragg angle θ (in degrees)? (answer up to two decimal places)	Atomic structure	24.00 TO 26.00	90
G-META-18-28	MCQS	94	Determine the correctness (or otherwise) of the following Assertion [A] and the Reason [R]. Assertion [A]: Refractory BCC metals like W and Mo are less ductile than FCC metals like Ni and Pt at room temperature. Reason [R]: BCC metals have fewer independent slip systems than FCC metals (A) Both [A] and [R] are true and [R] is the correct reason for [A] (B) Both [A] and [R] are true, but [R] is not the correct reason for [A] (C) Both [A] and [R] are false (D) [A] is true but [R] is false	Atomic structure	D	91
G-META-20-25	NUM	32	Given, crystal structure and atomic radius of Pb are FCC and 0.175 nm respectively. The number of atoms per unit area($nm^(-2)$) in (100) plane of Pb is?(round off to the nearest integer).	Atomic structure	7 TO 9	92
G-META-20-34	MCQS-NUM	47	Given, wavelength of the X-ray used is 0.1543nm. X-ray diffraction pattern from an elemental metal with a FCC crystal structure shows the first peak at a Bragg angle θ = 24.65°. The lattice parameter(in nm) of this metal is? (A) 0.185 (B) 0.262 (C) 0.320 (D) 0.370	Atomic structure	C	93
G-META-20-40	NUM	40	Assume hard sphere model and radius of Fe atom as 0.124 nm. Radius(in nm) of the largest interstitial atom that can be accommodated in an octahedral void in BCC iron without distorting the lattice is?(round off to three decimal places)	Atomic structure	0.018 TO 0.020	94
G-META-21-21	NUM	35	In the X-ray diffraction pattern of a FCC crystal, the first reflection occurs at a Bragg angle (θ) of 30°. The Bragg angle(in degree) for the second reflection will be?(round off to 1 decimal places)	Atomic structure	34.8 TO 36.1	95
G-META-21-25	NUM	36	Given: R = 8.314 J $mol^(-1)K^(-1)$. The vacancy concentration in a crystal doubles upon increasing the temperature from 27°C to 127°C. The enthalpy (in KJ $mol^(-1)$) of vacancy formation is? (round off to 2 decimal places).	Atomic structure	6.85 TO 7.00	96
G-META-21-53	NUM	38	Assume the radius of Fe atom to be 0.124 nm. The radius of an interstitial atom which just fits(without distorting the structure) inside an octahedral void of a bcc-iron crystal (in nm) is?(round off to 3 decimal places)	Atomic structure	0.017 TO 0.023	97
G-META-22-32	MCQS	36	While designing a material for high temperature application, which of the following characteristic(s)/attribute(s) is(are) desirable for achieving better creep resistance? (A) Fine grain size (B) FCC crystal structure (C) High melting point (D) Cold worked microstructure	Atomic structure	B,C	98
G-META-22-50	NUM	38	Consider a tilt boundary of misorientation of 2° in an aluminium grain. The lattice parameter of aluminium is 0.143 nm. The spacing(in nm) between the dislocations that form the tilt boundary is? (round off to 2 decimal places).	Atomic structure	2.86 TO 2.93	99
G-XEC-2012-13	MATCH	79	Match the properties in Column I with the options in Column II: Column I: [P. Toughness, Q. Resilience, R. Creep, S. Hardness] Column II: [1. Resistance to plastic deformation, 2. Time dependent permanent deformation under constant load, 3. Total elongation at failure, 4. Area under the stress-strain curve, 5. Area under the elastic part of the stress-strain curve] options: (A) P-5, Q-1, R-3, S-2 (B) P-4, Q-3, R-2, S-1 (C) P-4, Q-5, R-2, S-1 (D) P-5, Q-4, R-3, S-2	Mechanical	C	0
G-XEC-2012-19	MCQS-NUM	86	A 20 kN tensile load is applied axially to a steel bar of crosssectional area 8 $cm^2$ and 1m length. The Young’s modulus of steel ($E_(steel)$) is 200 GPa, and of aluminium ($E_(Al)$) is 70 GPa. The Poisson’s ratio (ν) can be taken as 0.3. When the same load is applied to an aluminium bar, it is found to give same elastic strain as the steel. Calculate the cross-sectional area of the aluminium bar. (A) 11.43 $cm^2$ (B) 14.93 $cm^2$ (C) 18.26 $cm^2$ (D) 22.86 $cm^2$	Mechanical	D	1
G-XEC-2014-7	MCQS	45	Which of the following mechanical properties of a material depend on the mobile dislocation density in it. (P) Young’s modulus (Q) yield strength (R) ductility (S) fracture toughness Options: (A) P, Q, R (B) Q, R, S (C) P, R, S (D) S, P, Q	Mechanical	B	2
G-XEC-2014-14	NUM	38	The Young’s modulus of a unidirectional SiC fiber reinforced Ti matrix composite is 185 GPa. If the Young’s moduli of Ti and SiC are 110 and 360 GPa respectively, the volume fraction of fibers in the composite is	Mechanical	0.29 to 0.31	3
G-XEC-2015-61-18	MCQS	53	Creep in metals is defined as (A) the maximum energy a solid can absorb elastically (B) the maximum energy a solid can absorb by plastic deformation (C) the stress at which plastic deformation starts (D) slow plastic deformation due to diffusion of atoms usually at high temperature (T > half the melting point)	Mechanical	D	4
G-XEC-2016-12	NUM	42	The yield strength of a ferritic steel increases from 120 MPa to 150 MPa when the grain size is decreased from 256 μm to 64 μm. When the grain size is further reduced to 16 μm, the expected yield strength(MPa) is ?	Mechanical	210 : 210	5
G-XEC-2017-6	MCQS	30	Ceramic materials fail at stresses much lower than their theoretical strength due to (A) Presence of dislocations (B) High elastic modulus (C) Presence of voids (D) Anisotropy in crystal structure	Mechanical	C	6
G-XEC-2017-11	NUM	55	A continuous, aligned carbon fibre (CF) reinforced polymer composite with 30 vol% of CF and rest resin was designed for a specific application. The modulus of elasticity of CF is 170 GPa and that of the resin is 3.0 GPa. The modulus of elasticity for this composite in the direction of fibre alignment in GPa	Mechanical	53 to 53.2	7
G-XEC-2018-1	MCQS	22	The stress ratio for a completely reversed cyclic loading during a fatigue test is (A) 0 (B) 1 (C) -1 (D) -1/2	Mechanical	C	8
G-XEC-2018-13	NUM	49	An infinite plate with a through-thickness crack of length 2 mm is subjected to a tensile stress (as shown in the figure). Assuming the plate to be linear elastic, the fracture stress in MPa (round off to the nearest whole number). (Given: Fracture toughness, $K_(1C)$ = 25 MPa √𝑚)	Mechanical	430 to 500	9
G-XEC-2019-4	MCQS	19	Which one of the following is time-independent? (A) Elastic deformation (B) Anelastic deformation (C) Viscoelastic deformation (D) Creep deformation	Mechanical	A	10
G-XEC-2022-3	MCQS	54	In an ideal rubber, the primary factor responsible for elasticity up to small strains is (A) Change in both enthalpy and entropy (B) Change in enthalpy, but no change in the entropy (C) No change in enthalpy, but change in the entropy (D) Neither a change in enthalpy, nor a change in the entropy	Mechanical	C	11
G-XEC-2022-14	MCQS	40	During the ageing of a homogenized Al-Cu alloy (1 to 4 wt.% Cu) below the GP zone solvus, hardness of the alloy: (A) increases monotonically (B) decreases monotonically (C) first increases and then decreases (D) first decreases and then increases	Mechanical	C	12
G-XEC-2013-21	NUM	44	A stress of 10 MPa is applied to an elastomer to generate a strain of 50%. The strain is held constant at this value. After 40 days at 20°C, the stress decreases to 5 MPa. What is the relaxation time constant for this material?	Mechanical	Marks to all	13
G-XEC-2013-22	NUM	45	A stress of 10 MPa is applied to an elastomer to generate a strain of 50%. The strain is held constant at this value. After 40 days at 20°C, the stress decreases to 5 MPa. What will be the stress after 60 days at 20°C?	Mechanical	Marks to all	14
G-XEC-2014-11	NUM	53	A bar of Ti with Young’s modulus of 110 GPa and yield strength of 880 MPa is tested in tension. It is noticed that the alloy does not exhibit any strain hardening and fails at a total strain of 0.108. The mechanical energy that is necessary to break the material in MJ/$m^3$ is	Mechanical	91 to 92	15
G-XEC-2016-6	NUM	10	Number of elements in a tensor of rank 4 is	Mechanical	81	16
G-XEC-2017-18	NUM	35	A ceramic material with a critical flaw size of 30 μm has fracture stress of 300 MPa. For the same material the fracture stress(in Mpa) for a critical flaw size of 90 μm will be?	Mechanical	172 TO 174	17
G-XEC-2019-16	NUM	51	Tensile true stress – true strain curve for plastic region of an alloy is given by 𝜎 (MPa)=600 $𝜀^𝑛$. When true strain is 0.05, the true stress is 350 MPa. For the same alloy, when engineering strain is 0.12 then the engineering stress(in MPa) is? (round off to the nearest integer)	Mechanical	360 to 364	18
G-XEC-2019-21	NUM	32	A piezoelectric material has a Young’s modulus of 72 GPa. The stress(in MPa) required to change the polarization from 640 to 645 C m $m^(-3)$ is. (round off to the nearest integer)	Mechanical	560 to 565	19
G-XEC-2021-18	NUM	56	Vickers hardness test is performed with an indenter of square-base diamond pyramid having an included angle of 136° between the opposite faces of the pyramid. If the applied load is 10 kg and the average length of diagonals of square indentation is 0.5 mm, the Vickers hardness in kg $mm^(−2)$ is? (round off to nearest integer)	Mechanical	71 to 77	20
G-XEC-2022-7	MCQS	56	Vickers microhardness (HV) of a ductile material A is higher than another ductile material B. Which of the following is/are true? (A) Young’s modulus of A is greater than B (B) Yield strength of A is greater than B (C) Scratch resistance of A is greater than B (D) Ductility of A is greater than B	Mechanical	B,C	21
G-META-12-21	MCQS	84	A polymer matrix composite is reinforced with long continuous ceramic fibres aligned in one direction. The Young’s moduli of the matrix and fibres are $E_m$ and $E_f$ respectively, and the volume fraction of the fibres is f. Assuming iso-stress condition, Young’s modulus of the composite $E_C$ in a direction perpendicular to the length of fibres, is given by the expression (A) $E_C$ = (1-f)$E_m$ + f$E_f$ (B) $E_C$ = f$E_m$ + (1-f)$E_f$ (C) 1/$E_C$ = [(1-f)/$E_m$] + f/$E_f$ (D) 1/$E_C$ = [f/$E_m$] + (1-f)/$E_f$	Mechanical	C	22
G-META-12-43	MATCH	66	Match the phenomena listed in Group I with the possible mechanisms in Group II: Group I: [P. Fatigue, Q. Creep, R. Strain hardening, S. Yield point phenomenon] Group II: [1. Grain boundary sliding, 2. Slip band extrusion and intrusion, 3. Cottrell atmosphere, 4. Dislocation interaction] Options: (A) P-2, Q-3, R-4, S-1 (B) P-2, Q-4, R-3, S-1 (C) P-2, Q-1, R-4, S-3 (D) P-1, Q-2, R-4, S-3	Mechanical	C	23
G-META-12-44	MCQS-NUM	42	Fracture stress for a brittle material having a crack length of 1 µm is 200 MPa. Fracture stress for the same material having a crack length of 4 µm is (A) 200 MPa (B) 150 MPa (C) 100 MPa (D) 50 MPa	Mechanical	C	24
G-META-12-45	MCQS-NUM	54	The flow stress (σ) of an alloy varies with strain rate (ε) as σ = 100* $(ε)^(0.1)$ MPa. When the alloy is hot extruded from 10 cm diameter to 5 cm diameter at a speed of 2 cm/s, the flow stress is (A) 1000 MPa (B) 105 MPa (C) 150 MPa (D) 1050 MPa	Mechanical	B	25
G-META-12-53	MCQS-NUM	42	A material with grain size of ASTM No. 6 has a lattice frictional stress 100 MN/$m^2$ and locking parameter (Hall-Petch constant) 0.10 MN/$m^(1.5)$. Yield strength of the material is approximately (A) 100 MPa (B) 115 MPa (C) 165 MPa (D) 215 MPa	Mechanical	B	26
G-META-13-9	MCQS	41	As compared to the engineering stress-engineering strain curve, the true stress-true strain curve for a given material (A) lies above and to the left (B) lies below and to the right (C) crosses the engineering stress-engineering strain curve (D) is identical	Mechanical	A	27
G-META-13-33	MCQS-NUM	49	The yield strength of a polycrystalline metal increases from 100 MPa to 145 MPa on decreasing the grain size from 64 µm to 25 µm. The yield strength of this metal (in MPa) having a grain size of 36 µm is (A) 110 (B) 125 (C) 140 (D) 165	Mechanical	B	28
G-META-14-2	MCQS	28	Which one of the following microstructures of a Ni-base superalloy imparts the highest creep resistance? (A) Fine grained equiaxed (B) Coarse grained equiaxed (C) Columnar (D) Single crystal	Mechanical	D	29
G-META-14-9	NUM	36	A tensile specimen was deformed at a constant crosshead speed of 6 mm/min. The strain rate at the start of the testing was 5 * $10^(-3)s^(-1)$. The initial gauge length of the specimen (in mm) was?	Mechanical	19.95 TO 20.05	30
G-META-14-17	NUM	35	A steel rod was subjected to a fluctuating stress cycle that varied between a maximum of 400 MPa in tension to a minimum of 300 MPa in compression. What is the stress amplitude, in MPa?	Mechanical	350 T0 350	31
G-META-14-19	MCQS	65	Identify the INCORRECT statement with respect to grain growth. (A) As the average grain size increases, the grain boundary energy per unit area decreases. (B) The driving force for grain growth is the decrease in grain boundary energy per unit volume of the material. (C) Higher the temperature, the faster is the grain growth. (D) Impurity atoms segregated at grain boundaries can retard grain growth	Mechanical	A	32
G-META-14-27	MCQS-NUM	38	A tensile specimen was deformed to a true strain of 0.405. The change in the gauge length was 5 mm. The final gauge length of the specimen, in mm, is (A) 10 (B) 12 (C) 15 (D) 18	Mechanical	C	33
G-META-14-38	NUM	39	A body starts yielding when it is subjected to a stress state with principal stresses of 250 MPa, 50 MPa and −50 MPa. What is the yield strength of the material, in MPa, if Tresca yield criterion is obeyed?	Mechanical	300	34
G-META-14-41	NUM	37	A rod of a metal with Young’s modulus of 200 GPa is pulled in tension to a stress of 400 MPa. What is the elastic strain (in %) that is recovered, when the rod is completely unloaded?	Mechanical	0.2	35
G-META-14-55	NUM	60	A glass fibre reinforced epoxy composite is made with 60 wt.% unidirectional continuous glass fibres. The elastic moduli of the glass fibre and the epoxy matrix are 72.5 and 2.4 GPa, respectively. What is the elastic modulus of this composite along the fibre direction, in GPa? The densities of glass fibre and epoxy are $2.58 g/cm^3$ and 1.14 $g/cm^3$, respectively.	Mechanical	30.0 TO 30.5	36
G-META-15-22	NUM	39	The stress required for Orowan dislocation bypass is 200 MPa in an alloy when the interprecipitate spacing is 500 nm. In the same alloy, if the inter-precipitate spacing is reduced to 200 nm, the stress required (in MPa) is?	Mechanical	490 TO 510	37
G-META-15-45	NUM	32	If a cylindrical billet of height 1.0 m and diameter 0.5 m is upset forged to form a cylindrical pancake of height 0.25 m, the diameter of the pancake (in m) is?	Mechanical	0.9 TO 1.1	38
G-META-15-49	NUM	39	The driving force for sintering a compact consisting of spherical particles of radius $R_1$ is $∆G_1$. If the particle size is reduced to $R_2$ = 0.1 $R_1$, the corresponding driving force $∆G_2$ = α $∆G_1$ , where α is	Mechanical	10	39
G-META-15-51	MATCH	73	Match the following fracture surface features listed in Group I with the fracture mechanisms listed in Group II: Group I: [P. Striations, Q. Dimples and microvoids, R. Flat facets and "river markings", S. Jagged surface with grain-like features] Group II: [1. Intergranular fracture, 2. Cleavage fracture, 3. Ductile fracture, 4. Fatigue fracture] Options: (A) P-1, Q-2, R-3, S-4 (B) P-1, Q-3, R-2, S-4 (C) P-4, Q-3, R-2, S-1 (D) P-2, Q-1, R-4, S-3	Mechanical	C	40
G-META-15-55	NUM	66	A brittle material is mechanically tested in medium P in which it has surface energy $𝛾_𝑠$= 0.9 J $m^(-2)$ . This material has a fracture strength of 300 MPa for a given flaw size. The same solid containing the same flaws is then tested in medium Q in which $𝛾_𝑠$= 0.1 J $m^(-2)$. The fracture strength (in MPa) in medium Q based on Griffith's theory is?	Mechanical	100	41
G-META-16-19	MCQS	22	Creep resistance decreases due to (A) Small grain size (B) Fine dispersoid size (C) Low stacking fault energy (D) High melting point	Mechanical	A	42
G-META-16-51	MCQS-NUM	37	Given: [$E_(glass fiber)$ = 70 GPa; $E_(polymer)$ = 3.5 GPa]. For a polymer reinforced with 40 vol.% glass fiber, the elastic modulus (in GPa) along the transverse direction is (A) 5.6 (B) 8.1 (C) 30.1 (D) 43.4	Mechanical	A	43
G-META-16-55	MATCH	61	Match the deformation processes in Column I with the corresponding stress states listed in Column II: Column I: [[P] Wire Drawing, [Q] Forging, [R] Stretch Forming, [S] Cutting] Column II: [[1] Direct Compression, [2] Indirect Compression, [3] Tension, [4] Shear] Options: (A) P-1; Q-2; R-3; S-4 (B) P-1; Q-2; R-4; S-3 (C) P-2; Q-1; R-3; S-4 (D) P-2; Q-1; R-4; S-3	Mechanical	C	44
G-META-17-18	MCQS	22	Stress required to operate a Frank-Read source of length L is approximately given by: (A) Gb/L (B) $Gb^2$/L (C) $Gb^(2)/L^(2)$ (D) $Gb^(2)/2L^2$	Mechanical	A	45
G-META-17-20	NUM	30	A rod is elastically deformed by a uniaxial stress resulting in a strain of 0.02. If the Poisson's ratio is 0.3, the volumetric strain is?(answer up to three decimal places)	Mechanical	0.006 TO 0.010	46
G-META-17-52	NUM	41	Given the young's modulus E = 4.5 GPa. A perfectly elastic-plastic material has a yield of 450 MPa and fractures at a strain of 0.45. The ratio of resilience to toughness for this material is? (answer up to three decimal places)	Mechanical	0.110 TO 0.140	47
G-META-18-29	MCQS	87	A glass fibre of 5 micron diameter is subjected to a tensile stress of 20 MPa. The surface energy and elastic modulus of this material are 0.3 $Jm^(-2)$ and 70 GPa, respectively. Pick the correct answer based on the information provided above: Note: The glass fibre contains a population of flaws of different lengths. (A) The fibre will undergo brittle fracture (B) The fibre will undergo plastic deformation, but not fracture (C) The fibre will undergo elastic deformation, but not fracture (D) The fibre will undergo buckling	Mechanical	C	48
G-META-18-41	NUM	65	A continuous and aligned carbon-fiber composite consists of 25 vol. % of fibers in an epoxy matrix. The Young’s modulus of fiber and matrix, respectively are $𝐸_𝑓$ = 250 GPa and $𝐸_𝑚$ = 2.5 GPa. If the composite is subjected to longitudinal loading (iso-strain condition and assuming elastic response), what is the fraction of load borne by the reinforcement rounded off to two decimal places?	Mechanical	0.96 TO 0.98	49
G-META-19-16	MCQS	31	During low strain rate (≤ 0.1 per second) deformation of a metal at room temperature, the one that deforms by twinning mode is (A) Fe (B) Mg (C) Al (D) Ni	Mechanical	B	50
G-META-19-17	MCQS	44	In a tensile creep test of a metal, Nabarro-Herring mechanism is favored over Coble mechanism for (A) larger grain size and lower temperature (B) smaller grain size and higher temperature (C) larger grain size and higher temperature (D) smaller grain size and lower temperature	Mechanical	C	51
G-META-19-18	MCQS	25	Beach marks are commonly observed on the fractured surfaces of metals after a (A) Creep test (B) Fatigue test (C) Impact test (D) Compression test	Mechanical	B	52
G-META-19-19	MCQS-NUM	45	The length of internal cracks in two samples of the same glass is measured to be $𝑐_1$ = 0.5 mm and $𝑐_2$ = 2 mm. The ratio ($𝜎_(1)/𝜎_(2)$) of the fracture strength of the two samples is (A) 0.5 (B) 1.0 (C) 2.0 (D) 4.0	Mechanical	C	53
G-META-19-36	NUM	70	A 50 cm long rod is placed against a vertical wall such that the bottom of the rod is 30 cm away from the wall. If the bottom of the rod is pulled horizontally away from the wall at 4 𝑐𝑚. $𝑠^(−1)$ , the top of the rod starts sliding down the wall with an instantaneous velocity (in 𝑐𝑚. $𝑠^(−1)$ , rounded off to two decimal places) of magnitude is?	Mechanical	2.90 TO 3.10	54
G-META-19-49	NUM	54	Given: Elastic moduli of A and B are 200 GPa and 100 GPa, respectively. A material, made up of alternating layers of metals A and B, is loaded as shown below. If the volume % of B is 25%, the elastic modulus (in GPa, rounded off to one decimal place) of the material is	Mechanical	155.0 T0 165.0	55
G-META-20-2	MCQS	19	The number of independent elastic constants of an isotropic material is: (A) 1 (B) 2 (C) 3 (D) 4	Mechanical	B	56
G-META-20-8	MCQS	27	For a material to exhibit superplasticity, one of the requirements is: (A) Coarse-grained microstructure (B) High strain-rate sensitivity (C) Low strain-hardening exponent (D) High modulus of elasticity	Mechanical	B	57
G-META-20-15	MCQS	49	The sequence of precipitation during aging of Al -4 wt.% Cu alloy is: (A) GP zone → θ`` → θ` → θ (B) GP zone → θ → θ` → θ`` (C) GP zone → θ` → θ`` → θ (D) θ`` → θ` → GP zone → θ	Mechanical	A	58
G-META-20-16	MCQS	26	The indenter used in Rockwell hardness measurements on C scale in (A) diamond cone (B) 10 mm steel ball (C) diamond pyramid (D) 1/16 in.steel ball	Mechanical	A	59
G-META-20-24	NUM	42	Given, the coefficient of friction between sheet and roll is 0.1. In cold-rolling, for the sheet to be drawn into rolls, the angel of contact(in degress) (or angle of bite) should be less than or equal to?(round off to one decimal places)	Mechanical	5.6 TO 5.8	60
G-META-21-7	MCQS	65	For uniaxial tensile stress-strain behaviour of polycrystalline aluminium, which one of the following statements is FALSE? (A) True stress is always higher than the engineerig stress. (B) At the ultimate stress point on the true stress-strain curve, dσ/dε = 0 (C) Resilience is the area under the elastic region of the engineering stress-strain curve. (D) Maximum true stress does not correspond to the maximum load.	Mechanical	B	61
G-META-21-8	MCQS	47	Which one of the following is FALSE for creep deformation? (A) The minimum creep rate is obtained in the primary stage (stage I) (B) Creep resistance decreases with decrease in grain size (C) Coble creep occurs via grain boundary diffusion. (D) Nabarro-Herring creep occurs via lattice diffusion	Mechanical	A	62
G-META-21-32	MCQS	67	A single crystal aluminium sample is subjected to uniaxial tension along [1 1 2] direction. If the applied tensile stress is 100 MPa and the critical resolved shear stress (CRSS) is 25 MPa, which one of the following slip systems will be activated? (A) [-1 0 1](1 1 1) (B) [-1 1 0](1 1 1) (C) [1 0 1](1 1 -1) (D) [0 1 1](1 1 -1)	Mechanical	A	63
G-META-21-47	NUM	50	In a material, a shear stress of 100 MPa is required to bow a dislocation line between precipitates with a spacing of 0.2 µm. If the spacing between the precipitates is increased to 0.5 µm, the shear stress (in MPa) to bow the dislocation would be?(round off to nearest integer)	Mechanical	40	64
G-META-22-26	MCQS	40	Given: σ = true stress and ϵ = true strain. For a material that undergoes strain hardening, necking instability occurs during tensile testing when (A) 𝑑𝜎/𝑑𝜖 = 0 (B) 𝑑𝜎/𝑑𝜖 = ϵ (C) 𝑑𝜎/𝑑𝜖 = σ (D) 𝑑𝜎/𝑑𝜖 = ∞	Mechanical	C	65
G-META-12-48	MCQS-NUM	91	A steel ball (density $ρ_(steel)$ = 7200 kg/$m^(3)$) is placed in an upward moving liquid Al (density $ρ_(Al)$ = 2360 kg/$m^(3)$, viscosity $μ_(Al)$ = 1$10^(–3)$ Pa.s and Reynolds number = 5$10^(5)$). The force (F) exerted on the steel ball is expressed as: F = f π $R^(2)$ ($ρ_(Al)$ $v^2$ /2) where, f is friction factor (=0.2), v is the velocity of liquid Al and R is the radius of steel ball. The force exerted on the steel ball is (A) 8.32 N (B) 6.70 N (C) 1.67 N (D) 0.52 N	Mechanical	A	66
G-META-12-54	MCQS-NUM	56	The strain hardening behaviour of an annealed rod during cold rolling is given by σ = 700 $(ε)^0.2$ MPa, where σ is the flow stress at strain ε. Flow stress after 50% reduction in area of the annealed rod on cold rolling is approximately (A) 750 MPa (B) 650 MPa (C) 609 MPa (D) 559 MPa	Mechanical	B	67
G-META-13-24	NUM	30	If σ and ε are true stress and true strain, respectively, the maximum true uniform strain that can be imparted to a material obeying σ = 1050 * $ε^(0.25)$ is	Mechanical	0.25	68
G-META-13-34	MCQS-NUM	41	In a brittle material, the maximum internal crack length is 8 µm. If Young’s modulus is 400 GPa and surface energy is 3.14 J/$m^2$ , the estimated theoretical fracture strength (in MPa) is (A) 375 (B) 412 (C) 327 (D) 447	Mechanical	D	69
G-META-13-36	MCQS-NUM	36	A 480 mm thick slab is hot-rolled using a roll of 720 mm diameter. For a coefficient of friction of 0.5, the maximum possible reduction (in mm) is (A) 90 (B) 180 (C) 240 (D) 360	Mechanical	A	70
G-META-13-46	NUM	24	The critical internal crack length (in mm) in a steel having $K_(1c)$ of 45 MPa√m to support a Mode-I stress of 400 MPa is?	Mechanical	7.9 TO 8.3	71
G-META-14-44	MCQS	94	Determine the correctness or otherwise of the following Assertion (a) and Reason (r). Assertion (a): Peak aging time for an Al-4 wt.% Cu alloy is indicated by a maximum in the hardness. Reason (r): The maximum volume fraction of the θ precipitates is formed at the peak aging time. (A) a is true but r is false (B) a is false but r is true (C) both a and r are true, and r is the reason for a (D) both a and r are true, but r is not the reason for a	Mechanical	A	72
G-META-14-49	NUM	49	The flow curve of an annealed metal is expressed as 𝜎 = $200𝜀^(0.25)$ , where σ is in MPa. If a rod of this metal is subjected to a true strain of ε = 0.3 by extrusion, the ideal plastic work of deformation per unit volume (in MJ/$m^3$) is	Mechanical	35 TO 36	73
G-META-16-25	NUM	32	A rolling mill has a roll diameter of 200 mm. If coefficient of friction is 0.1, then the maximum possible reduction (in mm) during rolling of a 250 mm thick plate is?	Mechanical	0.9 TO 1.1	74
G-META-16-48	NUM	63	Given data (for glass plate): Young’s Modulus = 70 GPa, Surface energy per unit area = 1 $J.m^(-2)$. A glass plate has two parallel cracks. One of them is an internal crack of length 5 μm and the other is a surface crack of length 3 μm. A tensile stress is applied perpendicular to the crack surfaces. The fracture stress (in MPa) is?	Mechanical	115 TO 125	75
G-META-16-49	NUM	37	A tensile stress is applied along the [100] direction in a FCC metal crystal. The critical resolved shear stress is 6 MPa. The tensile stress (in MPa) required for initiating slip on the (111) slip plane is?	Mechanical	14.0 TO 15.5	76
G-META-17-10	NUM	38	Tungsten powder is pressded at 150 MPa to a green density of 55%. After sintering, the compact attains 86.5% of its theoretical density. Assuming uniform shrinkage, the linear shrinkage (in %) is? (answer up to two decimal places)	Mechanical	13.30 TO 15.50	77
G-META-17-16	NUM	35	A brittle material (young's modulus = 60 GPa and surface energy = 0.5 $J.m^(-2)$) has a surface crack of length 2µm. The fracture strength (in MPa) of this material is?(answer up tp two decimal places)	Mechanical	95.00 TO 125.00	78
G-META-17-22	NUM	36	A material which shows power law behavior, σ = 50*$ε^(0.3)$, is being wire drawn. The maxium strain per pass in annealed condition (assume ideal work and efficiency η = 1) is?(answer up to two decimal places)	Mechanical	1.20 TO 1.40	79
G-META-17-48	NUM	72	A steel component is subjected to fatigue loading: σ(maximum) = 200 Mpa, σ (minimum) = 0. The component has an initial crack length of 1mm. Propogation of crack is governmed by da/dN = $10^(-12)$ $(ΔK)^3$, where, the crack length a is in meters, N is the number of cycles and ΔK is in $MPa.m^(1/2)$. The length of the crack (in m) after one million cycles will be?(answer up to three decimal places).	Mechanical	0.009 TO 0.015	80
G-META-18-24	NUM	44	A plate of thickness h = 120 mm is cold rolled in a mill with a roll diameter of 200 mm. If the coefficient of friction μ is 0.1, the maximum possible reduction Δh(in mm to one decimal place) in a single pass is	Mechanical	0.9 TO 1.1	81
G-META-18-46	NUM	42	A single crystal of aluminium is subjected to 10 MPa tensile stress along the [321] crystallographic direction. What is the value of the resolved shear stress on the (1 1 -1) [101] slip system in MPa rounded off to two decimal places?	Mechanical	4.5 TO 4.8	82
G-META-18-55	NUM	48	The ideal plastic work involved in extruding a cylindrical billet of length 100 mm, from an initial diameter of 20 mm to a final diameter of 16 mm is?(in J to one decimal place). The flow stress in compression is 40 MPa, and remains constant throughout the process.	Mechanical	555.5 TO 565.5	83
G-META-19-25	NUM	51	A plate of width 100 𝑐𝑚 and thickness 5 𝑐𝑚 is rolled to a thickness of 3 𝑐𝑚. If the entry velocity is 10 $𝑐𝑚.𝑠^(−1)$ , the exit velocity of the plate (in $𝑐𝑚.𝑠^(−1)$ , rounded off to one decimal place) is? Assume no change in the width of the plate	Mechanical	16.0 TO 17.4	84
G-META-19-32	MCQS	46	An aluminium single crystal is loaded in tension along [1 -1 0] axis. Among the following slip systems, the one that will be activated first is? (A) (1 -1 -1)[0 -1 1] (B) (-1 -1 1)[011] (C) (-1 -1 1)[1 -1 0] (D) (-1 -1 1)[101]	Mechanical	A	85

G-META-22-40

MATCH

136

Find the correct match between dislocation reactions (Column A) to the descriptions (Column B) Column A: [(P) $a_°$/2 [-1 -1 1] + $a_°$/2 [1 1 1] = $a_°$ [ 0 0 1], (Q) $a_°$/6 [-1 2 -1 ] + $a_°$/6 [1 -1 2] = $a_°$/6 [0 1 1], (R) $a_°$/6 [1 -2 1] + $a_°$/6[-1 -1 2] = $a_°$/2 [0 -1 1] ] Column B: [(1) Leading partials merging to form a Lomer-cottrell lock in an FCC metal, (2) Energetically unfavorable dislocation reaction in an FCC metal, (3) Typical dislocation reaction in a BCC metal] Options: (A) P - 3, Q - 2, R - 1 (B) P - 3, Q - 1, R - 2 (C) P - 2, Q - 3, R - 1 (D) P - 2, Q - 1, R - 3

Atomic structure

B

86

G-META-22-41

MCQS

115

Match the phenomena (Column I) with the descriptions (Column II) Column I: [(P) Cottrell atmosphere, (Q) Suzuki interaction, (R) Bauschinger effect, (S) Nabarro- Herring creep] Column II: [(1) Decrease in yield stress when loading direction is reversed, (2) Stress assisted diffusion of vacancies resulting in plastic deformation in a polycrystalline material, (3) Lüders bands, (4) Segregation of solutes to the stacking fault] Options: (A) P - 1, Q - 2, R - 3, S - 4 (B) P - 1, Q - 2, R - 4, S - 3 (C) P - 3, Q - 4, R - 1, S - 2 (D) P - 3, Q - 1, R - 4, S - 2

Atomic structure

C

87

G-META-14-31

MCQS

54

Dissociation of a dislocation into two partials in an FCC metal is given by the following equation. (a/2)[1 -1 0] → (a/6)[2 -1 1] + (a/6)[1 -2 -1] . On which plane do these two partial dislocaitons lie? (A) (-1 1 1) (B) (1 1 1) (C) (1 -1 1) (D) (1 1 -1)

Atomic structure

D

88

G-META-16-12

NUM

22

The lattice parameter of face-centered cubic iron (γ-Fe) is 0.3571 nm. The radius (in nm) of the octahedral void in γ-Fe is?

Atomic structure

0.045 TO 0.06

89

G-META-17-19

NUM

40

Given: $λ_(CuKα)$ = 0.154 nm; lattice parameter of the metal = 0.36 nm. The second peak in the powder X-ray diffraction pattern of a FCC metal occurs at what Bragg angle θ (in degrees)? (answer up to two decimal places)

Atomic structure

24.00 TO 26.00

90

G-META-18-28

MCQS

94

Determine the correctness (or otherwise) of the following Assertion [A] and the Reason [R]. Assertion [A]: Refractory BCC metals like W and Mo are less ductile than FCC metals like Ni and Pt at room temperature. Reason [R]: BCC metals have fewer independent slip systems than FCC metals (A) Both [A] and [R] are true and [R] is the correct reason for [A] (B) Both [A] and [R] are true, but [R] is not the correct reason for [A] (C) Both [A] and [R] are false (D) [A] is true but [R] is false

Atomic structure

D

91

G-META-20-25

NUM

32

Given, crystal structure and atomic radius of Pb are FCC and 0.175 nm respectively. The number of atoms per unit area($nm^(-2)$) in (100) plane of Pb is?(round off to the nearest integer).

Atomic structure

7 TO 9

92

G-META-20-34

MCQS-NUM

47

Given, wavelength of the X-ray used is 0.1543nm. X-ray diffraction pattern from an elemental metal with a FCC crystal structure shows the first peak at a Bragg angle θ = 24.65°. The lattice parameter(in nm) of this metal is? (A) 0.185 (B) 0.262 (C) 0.320 (D) 0.370

Atomic structure

C

93

G-META-20-40

NUM

40

Assume hard sphere model and radius of Fe atom as 0.124 nm. Radius(in nm) of the largest interstitial atom that can be accommodated in an octahedral void in BCC iron without distorting the lattice is?(round off to three decimal places)

Atomic structure

0.018 TO 0.020

94

G-META-21-21

NUM

35

In the X-ray diffraction pattern of a FCC crystal, the first reflection occurs at a Bragg angle (θ) of 30°. The Bragg angle(in degree) for the second reflection will be?(round off to 1 decimal places)

Atomic structure

34.8 TO 36.1

95

G-META-21-25

NUM

36

Given: R = 8.314 J $mol^(-1)K^(-1)$. The vacancy concentration in a crystal doubles upon increasing the temperature from 27°C to 127°C. The enthalpy (in KJ $mol^(-1)$) of vacancy formation is? (round off to 2 decimal places).

Atomic structure

6.85 TO 7.00

96

G-META-21-53

NUM

38

Assume the radius of Fe atom to be 0.124 nm. The radius of an interstitial atom which just fits(without distorting the structure) inside an octahedral void of a bcc-iron crystal (in nm) is?(round off to 3 decimal places)

Atomic structure

0.017 TO 0.023

97

G-META-22-32

MCQS

36

While designing a material for high temperature application, which of the following characteristic(s)/attribute(s) is(are) desirable for achieving better creep resistance? (A) Fine grain size (B) FCC crystal structure (C) High melting point (D) Cold worked microstructure

Atomic structure

B,C

98

G-META-22-50

NUM

38

Consider a tilt boundary of misorientation of 2° in an aluminium grain. The lattice parameter of aluminium is 0.143 nm. The spacing(in nm) between the dislocations that form the tilt boundary is? (round off to 2 decimal places).

Atomic structure

2.86 TO 2.93

99

G-XEC-2012-13

MATCH

79

Match the properties in Column I with the options in Column II: Column I: [P. Toughness, Q. Resilience, R. Creep, S. Hardness] Column II: [1. Resistance to plastic deformation, 2. Time dependent permanent deformation under constant load, 3. Total elongation at failure, 4. Area under the stress-strain curve, 5. Area under the elastic part of the stress-strain curve] options: (A) P-5, Q-1, R-3, S-2 (B) P-4, Q-3, R-2, S-1 (C) P-4, Q-5, R-2, S-1 (D) P-5, Q-4, R-3, S-2

Mechanical

C

0

G-XEC-2012-19

MCQS-NUM

86

A 20 kN tensile load is applied axially to a steel bar of crosssectional area 8 $cm^2$ and 1m length. The Young’s modulus of steel ($E_(steel)$) is 200 GPa, and of aluminium ($E_(Al)$) is 70 GPa. The Poisson’s ratio (ν) can be taken as 0.3. When the same load is applied to an aluminium bar, it is found to give same elastic strain as the steel. Calculate the cross-sectional area of the aluminium bar. (A) 11.43 $cm^2$ (B) 14.93 $cm^2$ (C) 18.26 $cm^2$ (D) 22.86 $cm^2$

Mechanical

D

1

G-XEC-2014-7

MCQS

45

Which of the following mechanical properties of a material depend on the mobile dislocation density in it. (P) Young’s modulus (Q) yield strength (R) ductility (S) fracture toughness Options: (A) P, Q, R (B) Q, R, S (C) P, R, S (D) S, P, Q

Mechanical

B

2

G-XEC-2014-14

NUM

38

The Young’s modulus of a unidirectional SiC fiber reinforced Ti matrix composite is 185 GPa. If the Young’s moduli of Ti and SiC are 110 and 360 GPa respectively, the volume fraction of fibers in the composite is

Mechanical

0.29 to 0.31

3

G-XEC-2015-61-18

MCQS

53

Creep in metals is defined as (A) the maximum energy a solid can absorb elastically (B) the maximum energy a solid can absorb by plastic deformation (C) the stress at which plastic deformation starts (D) slow plastic deformation due to diffusion of atoms usually at high temperature (T > half the melting point)

Mechanical

D

4

G-XEC-2016-12

NUM

42

The yield strength of a ferritic steel increases from 120 MPa to 150 MPa when the grain size is decreased from 256 μm to 64 μm. When the grain size is further reduced to 16 μm, the expected yield strength(MPa) is ?

Mechanical

210 : 210

5

G-XEC-2017-6

MCQS

30

Ceramic materials fail at stresses much lower than their theoretical strength due to (A) Presence of dislocations (B) High elastic modulus (C) Presence of voids (D) Anisotropy in crystal structure

Mechanical

C

6

G-XEC-2017-11

NUM

55

A continuous, aligned carbon fibre (CF) reinforced polymer composite with 30 vol% of CF and rest resin was designed for a specific application. The modulus of elasticity of CF is 170 GPa and that of the resin is 3.0 GPa. The modulus of elasticity for this composite in the direction of fibre alignment in GPa

Mechanical

53 to 53.2

7

G-XEC-2018-1

MCQS

22

The stress ratio for a completely reversed cyclic loading during a fatigue test is (A) 0 (B) 1 (C) -1 (D) -1/2

Mechanical

C

8

G-XEC-2018-13

NUM

49

An infinite plate with a through-thickness crack of length 2 mm is subjected to a tensile stress (as shown in the figure). Assuming the plate to be linear elastic, the fracture stress in MPa (round off to the nearest whole number). (Given: Fracture toughness, $K_(1C)$ = 25 MPa √𝑚)

Mechanical

430 to 500

9

G-XEC-2019-4

MCQS

19

Which one of the following is time-independent? (A) Elastic deformation (B) Anelastic deformation (C) Viscoelastic deformation (D) Creep deformation

Mechanical

A

10

G-XEC-2022-3

MCQS

54

In an ideal rubber, the primary factor responsible for elasticity up to small strains is (A) Change in both enthalpy and entropy (B) Change in enthalpy, but no change in the entropy (C) No change in enthalpy, but change in the entropy (D) Neither a change in enthalpy, nor a change in the entropy

Mechanical

C

11

G-XEC-2022-14

MCQS

40

During the ageing of a homogenized Al-Cu alloy (1 to 4 wt.% Cu) below the GP zone solvus, hardness of the alloy: (A) increases monotonically (B) decreases monotonically (C) first increases and then decreases (D) first decreases and then increases

Mechanical

C

12

G-XEC-2013-21

NUM

44

A stress of 10 MPa is applied to an elastomer to generate a strain of 50%. The strain is held constant at this value. After 40 days at 20°C, the stress decreases to 5 MPa. What is the relaxation time constant for this material?

Mechanical

Marks to all

13

G-XEC-2013-22

NUM

45

A stress of 10 MPa is applied to an elastomer to generate a strain of 50%. The strain is held constant at this value. After 40 days at 20°C, the stress decreases to 5 MPa. What will be the stress after 60 days at 20°C?

Mechanical

Marks to all

14

G-XEC-2014-11

NUM

53

A bar of Ti with Young’s modulus of 110 GPa and yield strength of 880 MPa is tested in tension. It is noticed that the alloy does not exhibit any strain hardening and fails at a total strain of 0.108. The mechanical energy that is necessary to break the material in MJ/$m^3$ is

Mechanical

91 to 92

15

G-XEC-2016-6

NUM

10

Number of elements in a tensor of rank 4 is

Mechanical

81

16

G-XEC-2017-18

NUM

35

A ceramic material with a critical flaw size of 30 μm has fracture stress of 300 MPa. For the same material the fracture stress(in Mpa) for a critical flaw size of 90 μm will be?

Mechanical

172 TO 174

17

G-XEC-2019-16

NUM

51

Tensile true stress – true strain curve for plastic region of an alloy is given by 𝜎 (MPa)=600 $𝜀^𝑛$. When true strain is 0.05, the true stress is 350 MPa. For the same alloy, when engineering strain is 0.12 then the engineering stress(in MPa) is? (round off to the nearest integer)

Mechanical

360 to 364

18

G-XEC-2019-21

NUM

32

A piezoelectric material has a Young’s modulus of 72 GPa. The stress(in MPa) required to change the polarization from 640 to 645 C m $m^(-3)$ is. (round off to the nearest integer)

Mechanical

560 to 565

19

G-XEC-2021-18

NUM

56

Vickers hardness test is performed with an indenter of square-base diamond pyramid having an included angle of 136° between the opposite faces of the pyramid. If the applied load is 10 kg and the average length of diagonals of square indentation is 0.5 mm, the Vickers hardness in kg $mm^(−2)$ is? (round off to nearest integer)

Mechanical

71 to 77

20

G-XEC-2022-7

MCQS

56

Vickers microhardness (HV) of a ductile material A is higher than another ductile material B. Which of the following is/are true? (A) Young’s modulus of A is greater than B (B) Yield strength of A is greater than B (C) Scratch resistance of A is greater than B (D) Ductility of A is greater than B

Mechanical

B,C

21

G-META-12-21

MCQS

84

A polymer matrix composite is reinforced with long continuous ceramic fibres aligned in one direction. The Young’s moduli of the matrix and fibres are $E_m$ and $E_f$ respectively, and the volume fraction of the fibres is f. Assuming iso-stress condition, Young’s modulus of the composite $E_C$ in a direction perpendicular to the length of fibres, is given by the expression (A) $E_C$ = (1-f)$E_m$ + f$E_f$ (B) $E_C$ = f$E_m$ + (1-f)$E_f$ (C) 1/$E_C$ = [(1-f)/$E_m$] + f/$E_f$ (D) 1/$E_C$ = [f/$E_m$] + (1-f)/$E_f$

Mechanical

C

22

G-META-12-43

MATCH

66

Match the phenomena listed in Group I with the possible mechanisms in Group II: Group I: [P. Fatigue, Q. Creep, R. Strain hardening, S. Yield point phenomenon] Group II: [1. Grain boundary sliding, 2. Slip band extrusion and intrusion, 3. Cottrell atmosphere, 4. Dislocation interaction] Options: (A) P-2, Q-3, R-4, S-1 (B) P-2, Q-4, R-3, S-1 (C) P-2, Q-1, R-4, S-3 (D) P-1, Q-2, R-4, S-3

Mechanical

C

23

G-META-12-44

MCQS-NUM

42

Fracture stress for a brittle material having a crack length of 1 µm is 200 MPa. Fracture stress for the same material having a crack length of 4 µm is (A) 200 MPa (B) 150 MPa (C) 100 MPa (D) 50 MPa

Mechanical

C

24

G-META-12-45

MCQS-NUM

54

The flow stress (σ) of an alloy varies with strain rate (ε) as σ = 100* $(ε)^(0.1)$ MPa. When the alloy is hot extruded from 10 cm diameter to 5 cm diameter at a speed of 2 cm/s, the flow stress is (A) 1000 MPa (B) 105 MPa (C) 150 MPa (D) 1050 MPa

Mechanical

B

25

G-META-12-53

MCQS-NUM

42

A material with grain size of ASTM No. 6 has a lattice frictional stress 100 MN/$m^2$ and locking parameter (Hall-Petch constant) 0.10 MN/$m^(1.5)$. Yield strength of the material is approximately (A) 100 MPa (B) 115 MPa (C) 165 MPa (D) 215 MPa

Mechanical

B

26

G-META-13-9

MCQS

41

As compared to the engineering stress-engineering strain curve, the true stress-true strain curve for a given material (A) lies above and to the left (B) lies below and to the right (C) crosses the engineering stress-engineering strain curve (D) is identical

Mechanical

A

27

G-META-13-33

MCQS-NUM

49

The yield strength of a polycrystalline metal increases from 100 MPa to 145 MPa on decreasing the grain size from 64 µm to 25 µm. The yield strength of this metal (in MPa) having a grain size of 36 µm is (A) 110 (B) 125 (C) 140 (D) 165

Mechanical

B

28

G-META-14-2

MCQS

28

Which one of the following microstructures of a Ni-base superalloy imparts the highest creep resistance? (A) Fine grained equiaxed (B) Coarse grained equiaxed (C) Columnar (D) Single crystal

Mechanical

D

29

G-META-14-9

NUM

36

A tensile specimen was deformed at a constant crosshead speed of 6 mm/min. The strain rate at the start of the testing was 5 * $10^(-3)s^(-1)$. The initial gauge length of the specimen (in mm) was?

Mechanical

19.95 TO 20.05

30

G-META-14-17

NUM

35

A steel rod was subjected to a fluctuating stress cycle that varied between a maximum of 400 MPa in tension to a minimum of 300 MPa in compression. What is the stress amplitude, in MPa?

Mechanical

350 T0 350

31

G-META-14-19

MCQS

65

Identify the INCORRECT statement with respect to grain growth. (A) As the average grain size increases, the grain boundary energy per unit area decreases. (B) The driving force for grain growth is the decrease in grain boundary energy per unit volume of the material. (C) Higher the temperature, the faster is the grain growth. (D) Impurity atoms segregated at grain boundaries can retard grain growth

Mechanical

A

32

G-META-14-27

MCQS-NUM

38

A tensile specimen was deformed to a true strain of 0.405. The change in the gauge length was 5 mm. The final gauge length of the specimen, in mm, is (A) 10 (B) 12 (C) 15 (D) 18

Mechanical

C

33

G-META-14-38

NUM

39

A body starts yielding when it is subjected to a stress state with principal stresses of 250 MPa, 50 MPa and −50 MPa. What is the yield strength of the material, in MPa, if Tresca yield criterion is obeyed?

Mechanical

300

34

G-META-14-41

NUM

37

A rod of a metal with Young’s modulus of 200 GPa is pulled in tension to a stress of 400 MPa. What is the elastic strain (in %) that is recovered, when the rod is completely unloaded?

Mechanical

0.2

35

G-META-14-55

NUM

60

A glass fibre reinforced epoxy composite is made with 60 wt.% unidirectional continuous glass fibres. The elastic moduli of the glass fibre and the epoxy matrix are 72.5 and 2.4 GPa, respectively. What is the elastic modulus of this composite along the fibre direction, in GPa? The densities of glass fibre and epoxy are $2.58 g/cm^3$ and 1.14 $g/cm^3$, respectively.

Mechanical

30.0 TO 30.5

36

G-META-15-22

NUM

39

The stress required for Orowan dislocation bypass is 200 MPa in an alloy when the interprecipitate spacing is 500 nm. In the same alloy, if the inter-precipitate spacing is reduced to 200 nm, the stress required (in MPa) is?

Mechanical

490 TO 510

37

G-META-15-45

NUM

32

If a cylindrical billet of height 1.0 m and diameter 0.5 m is upset forged to form a cylindrical pancake of height 0.25 m, the diameter of the pancake (in m) is?

Mechanical

0.9 TO 1.1

38

G-META-15-49

NUM

39

The driving force for sintering a compact consisting of spherical particles of radius $R_1$ is $∆G_1$. If the particle size is reduced to $R_2$ = 0.1 $R_1$, the corresponding driving force $∆G_2$ = α $∆G_1$ , where α is

Mechanical

10

39

G-META-15-51

MATCH

73

Match the following fracture surface features listed in Group I with the fracture mechanisms listed in Group II: Group I: [P. Striations, Q. Dimples and microvoids, R. Flat facets and "river markings", S. Jagged surface with grain-like features] Group II: [1. Intergranular fracture, 2. Cleavage fracture, 3. Ductile fracture, 4. Fatigue fracture] Options: (A) P-1, Q-2, R-3, S-4 (B) P-1, Q-3, R-2, S-4 (C) P-4, Q-3, R-2, S-1 (D) P-2, Q-1, R-4, S-3

Mechanical

C

40

G-META-15-55

NUM

66

A brittle material is mechanically tested in medium P in which it has surface energy $𝛾_𝑠$= 0.9 J $m^(-2)$ . This material has a fracture strength of 300 MPa for a given flaw size. The same solid containing the same flaws is then tested in medium Q in which $𝛾_𝑠$= 0.1 J $m^(-2)$. The fracture strength (in MPa) in medium Q based on Griffith's theory is?

Mechanical

100

41

G-META-16-19

MCQS

22

Creep resistance decreases due to (A) Small grain size (B) Fine dispersoid size (C) Low stacking fault energy (D) High melting point

Mechanical

A

42

G-META-16-51

MCQS-NUM

37

Given: [$E_(glass fiber)$ = 70 GPa; $E_(polymer)$ = 3.5 GPa]. For a polymer reinforced with 40 vol.% glass fiber, the elastic modulus (in GPa) along the transverse direction is (A) 5.6 (B) 8.1 (C) 30.1 (D) 43.4

Mechanical

A

43

G-META-16-55

MATCH

61

Match the deformation processes in Column I with the corresponding stress states listed in Column II: Column I: [[P] Wire Drawing, [Q] Forging, [R] Stretch Forming, [S] Cutting] Column II: [[1] Direct Compression, [2] Indirect Compression, [3] Tension, [4] Shear] Options: (A) P-1; Q-2; R-3; S-4 (B) P-1; Q-2; R-4; S-3 (C) P-2; Q-1; R-3; S-4 (D) P-2; Q-1; R-4; S-3

Mechanical

C

44

G-META-17-18

MCQS

22

Stress required to operate a Frank-Read source of length L is approximately given by: (A) Gb/L (B) $Gb^2$/L (C) $Gb^(2)/L^(2)$ (D) $Gb^(2)/2L^2$

Mechanical

A

45

G-META-17-20

NUM

30

A rod is elastically deformed by a uniaxial stress resulting in a strain of 0.02. If the Poisson's ratio is 0.3, the volumetric strain is?(answer up to three decimal places)

Mechanical

0.006 TO 0.010

46

G-META-17-52

NUM

41

Given the young's modulus E = 4.5 GPa. A perfectly elastic-plastic material has a yield of 450 MPa and fractures at a strain of 0.45. The ratio of resilience to toughness for this material is? (answer up to three decimal places)

Mechanical

0.110 TO 0.140

47

G-META-18-29

MCQS

87

A glass fibre of 5 micron diameter is subjected to a tensile stress of 20 MPa. The surface energy and elastic modulus of this material are 0.3 $Jm^(-2)$ and 70 GPa, respectively. Pick the correct answer based on the information provided above: Note: The glass fibre contains a population of flaws of different lengths. (A) The fibre will undergo brittle fracture (B) The fibre will undergo plastic deformation, but not fracture (C) The fibre will undergo elastic deformation, but not fracture (D) The fibre will undergo buckling

Mechanical

C

48

G-META-18-41

NUM

65

A continuous and aligned carbon-fiber composite consists of 25 vol. % of fibers in an epoxy matrix. The Young’s modulus of fiber and matrix, respectively are $𝐸_𝑓$ = 250 GPa and $𝐸_𝑚$ = 2.5 GPa. If the composite is subjected to longitudinal loading (iso-strain condition and assuming elastic response), what is the fraction of load borne by the reinforcement rounded off to two decimal places?

Mechanical

0.96 TO 0.98

49

G-META-19-16

MCQS

31

During low strain rate (≤ 0.1 per second) deformation of a metal at room temperature, the one that deforms by twinning mode is (A) Fe (B) Mg (C) Al (D) Ni

Mechanical

B

50

G-META-19-17

MCQS

44

In a tensile creep test of a metal, Nabarro-Herring mechanism is favored over Coble mechanism for (A) larger grain size and lower temperature (B) smaller grain size and higher temperature (C) larger grain size and higher temperature (D) smaller grain size and lower temperature

Mechanical

C

51

G-META-19-18

MCQS

25

Beach marks are commonly observed on the fractured surfaces of metals after a (A) Creep test (B) Fatigue test (C) Impact test (D) Compression test

Mechanical

B

52

G-META-19-19

MCQS-NUM

45

The length of internal cracks in two samples of the same glass is measured to be $𝑐_1$ = 0.5 mm and $𝑐_2$ = 2 mm. The ratio ($𝜎_(1)/𝜎_(2)$) of the fracture strength of the two samples is (A) 0.5 (B) 1.0 (C) 2.0 (D) 4.0

Mechanical

C

53

G-META-19-36

NUM

70

A 50 cm long rod is placed against a vertical wall such that the bottom of the rod is 30 cm away from the wall. If the bottom of the rod is pulled horizontally away from the wall at 4 𝑐𝑚. $𝑠^(−1)$ , the top of the rod starts sliding down the wall with an instantaneous velocity (in 𝑐𝑚. $𝑠^(−1)$ , rounded off to two decimal places) of magnitude is?

Mechanical

2.90 TO 3.10

54

G-META-19-49

NUM

54

Given: Elastic moduli of A and B are 200 GPa and 100 GPa, respectively. A material, made up of alternating layers of metals A and B, is loaded as shown below. If the volume % of B is 25%, the elastic modulus (in GPa, rounded off to one decimal place) of the material is

Mechanical

155.0 T0 165.0

55

G-META-20-2

MCQS

19

The number of independent elastic constants of an isotropic material is: (A) 1 (B) 2 (C) 3 (D) 4

Mechanical

B

56

G-META-20-8

MCQS

27

For a material to exhibit superplasticity, one of the requirements is: (A) Coarse-grained microstructure (B) High strain-rate sensitivity (C) Low strain-hardening exponent (D) High modulus of elasticity

Mechanical

B

57

G-META-20-15

MCQS

49

The sequence of precipitation during aging of Al -4 wt.% Cu alloy is: (A) GP zone → θ`` → θ` → θ (B) GP zone → θ → θ` → θ`` (C) GP zone → θ` → θ`` → θ (D) θ`` → θ` → GP zone → θ

Mechanical

A

58

G-META-20-16

MCQS

26

The indenter used in Rockwell hardness measurements on C scale in (A) diamond cone (B) 10 mm steel ball (C) diamond pyramid (D) 1/16 in.steel ball

Mechanical

A

59

G-META-20-24

NUM

42

Given, the coefficient of friction between sheet and roll is 0.1. In cold-rolling, for the sheet to be drawn into rolls, the angel of contact(in degress) (or angle of bite) should be less than or equal to?(round off to one decimal places)

Mechanical

5.6 TO 5.8

60

G-META-21-7

MCQS

65

For uniaxial tensile stress-strain behaviour of polycrystalline aluminium, which one of the following statements is FALSE? (A) True stress is always higher than the engineerig stress. (B) At the ultimate stress point on the true stress-strain curve, dσ/dε = 0 (C) Resilience is the area under the elastic region of the engineering stress-strain curve. (D) Maximum true stress does not correspond to the maximum load.

Mechanical

B

61

G-META-21-8

MCQS

47

Which one of the following is FALSE for creep deformation? (A) The minimum creep rate is obtained in the primary stage (stage I) (B) Creep resistance decreases with decrease in grain size (C) Coble creep occurs via grain boundary diffusion. (D) Nabarro-Herring creep occurs via lattice diffusion

Mechanical

A

62

G-META-21-32

MCQS

67

A single crystal aluminium sample is subjected to uniaxial tension along [1 1 2] direction. If the applied tensile stress is 100 MPa and the critical resolved shear stress (CRSS) is 25 MPa, which one of the following slip systems will be activated? (A) [-1 0 1](1 1 1) (B) [-1 1 0](1 1 1) (C) [1 0 1](1 1 -1) (D) [0 1 1](1 1 -1)

Mechanical

A

63

G-META-21-47

NUM

50

In a material, a shear stress of 100 MPa is required to bow a dislocation line between precipitates with a spacing of 0.2 µm. If the spacing between the precipitates is increased to 0.5 µm, the shear stress (in MPa) to bow the dislocation would be?(round off to nearest integer)

Mechanical

40

64

G-META-22-26

MCQS

40

Given: σ = true stress and ϵ = true strain. For a material that undergoes strain hardening, necking instability occurs during tensile testing when (A) 𝑑𝜎/𝑑𝜖 = 0 (B) 𝑑𝜎/𝑑𝜖 = ϵ (C) 𝑑𝜎/𝑑𝜖 = σ (D) 𝑑𝜎/𝑑𝜖 = ∞

Mechanical

C

65

G-META-12-48

MCQS-NUM

91

A steel ball (density $ρ_(steel)$ = 7200 kg/$m^(3)$) is placed in an upward moving liquid Al (density $ρ_(Al)$ = 2360 kg/$m^(3)$, viscosity $μ_(Al)$ = 1*$10^(–3)$ Pa.s and Reynolds number = 5*$10^(5)$). The force (F) exerted on the steel ball is expressed as: F = f π $R^(2)$ ($ρ_(Al)$ $v^2$ /2) where, f is friction factor (=0.2), v is the velocity of liquid Al and R is the radius of steel ball. The force exerted on the steel ball is (A) 8.32 N (B) 6.70 N (C) 1.67 N (D) 0.52 N

Mechanical

A

66

G-META-12-54

MCQS-NUM

56

The strain hardening behaviour of an annealed rod during cold rolling is given by σ = 700 $(ε)^0.2$ MPa, where σ is the flow stress at strain ε. Flow stress after 50% reduction in area of the annealed rod on cold rolling is approximately (A) 750 MPa (B) 650 MPa (C) 609 MPa (D) 559 MPa

Mechanical

B

67

G-META-13-24

NUM

30

If σ and ε are true stress and true strain, respectively, the maximum true uniform strain that can be imparted to a material obeying σ = 1050 * $ε^(0.25)$ is

Mechanical

0.25

68

G-META-13-34

MCQS-NUM

41

In a brittle material, the maximum internal crack length is 8 µm. If Young’s modulus is 400 GPa and surface energy is 3.14 J/$m^2$ , the estimated theoretical fracture strength (in MPa) is (A) 375 (B) 412 (C) 327 (D) 447

Mechanical

D

69

G-META-13-36

MCQS-NUM

36

A 480 mm thick slab is hot-rolled using a roll of 720 mm diameter. For a coefficient of friction of 0.5, the maximum possible reduction (in mm) is (A) 90 (B) 180 (C) 240 (D) 360

Mechanical

A

70

G-META-13-46

NUM

24

The critical internal crack length (in mm) in a steel having $K_(1c)$ of 45 MPa√m to support a Mode-I stress of 400 MPa is?

Mechanical

7.9 TO 8.3

71

G-META-14-44

MCQS

94

Determine the correctness or otherwise of the following Assertion (a) and Reason (r). Assertion (a): Peak aging time for an Al-4 wt.% Cu alloy is indicated by a maximum in the hardness. Reason (r): The maximum volume fraction of the θ precipitates is formed at the peak aging time. (A) a is true but r is false (B) a is false but r is true (C) both a and r are true, and r is the reason for a (D) both a and r are true, but r is not the reason for a

Mechanical

A

72

G-META-14-49

NUM

49

The flow curve of an annealed metal is expressed as 𝜎 = $200𝜀^(0.25)$ , where σ is in MPa. If a rod of this metal is subjected to a true strain of ε = 0.3 by extrusion, the ideal plastic work of deformation per unit volume (in MJ/$m^3$) is

Mechanical

35 TO 36

73

G-META-16-25

NUM

32

A rolling mill has a roll diameter of 200 mm. If coefficient of friction is 0.1, then the maximum possible reduction (in mm) during rolling of a 250 mm thick plate is?

Mechanical

0.9 TO 1.1

74

G-META-16-48

NUM

63

Given data (for glass plate): Young’s Modulus = 70 GPa, Surface energy per unit area = 1 $J.m^(-2)$. A glass plate has two parallel cracks. One of them is an internal crack of length 5 μm and the other is a surface crack of length 3 μm. A tensile stress is applied perpendicular to the crack surfaces. The fracture stress (in MPa) is?

Mechanical

115 TO 125

75

G-META-16-49

NUM

37

A tensile stress is applied along the [100] direction in a FCC metal crystal. The critical resolved shear stress is 6 MPa. The tensile stress (in MPa) required for initiating slip on the (111) slip plane is?

Mechanical

14.0 TO 15.5

76

G-META-17-10

NUM

38

Tungsten powder is pressded at 150 MPa to a green density of 55%. After sintering, the compact attains 86.5% of its theoretical density. Assuming uniform shrinkage, the linear shrinkage (in %) is? (answer up to two decimal places)

Mechanical

13.30 TO 15.50

77

G-META-17-16

NUM

35

A brittle material (young's modulus = 60 GPa and surface energy = 0.5 $J.m^(-2)$) has a surface crack of length 2µm. The fracture strength (in MPa) of this material is?(answer up tp two decimal places)

Mechanical

95.00 TO 125.00

78

G-META-17-22

NUM

36

A material which shows power law behavior, σ = 50*$ε^(0.3)$, is being wire drawn. The maxium strain per pass in annealed condition (assume ideal work and efficiency η = 1) is?(answer up to two decimal places)

Mechanical

1.20 TO 1.40

79

G-META-17-48

NUM

72

A steel component is subjected to fatigue loading: σ(maximum) = 200 Mpa, σ (minimum) = 0. The component has an initial crack length of 1mm. Propogation of crack is governmed by da/dN = $10^(-12)$ $(ΔK)^3$, where, the crack length a is in meters, N is the number of cycles and ΔK is in $MPa.m^(1/2)$. The length of the crack (in m) after one million cycles will be?(answer up to three decimal places).

Mechanical

0.009 TO 0.015

80

G-META-18-24

NUM

44

A plate of thickness h = 120 mm is cold rolled in a mill with a roll diameter of 200 mm. If the coefficient of friction μ is 0.1, the maximum possible reduction Δh(in mm to one decimal place) in a single pass is

Mechanical

0.9 TO 1.1

81

G-META-18-46

NUM

42

A single crystal of aluminium is subjected to 10 MPa tensile stress along the [321] crystallographic direction. What is the value of the resolved shear stress on the (1 1 -1) [101] slip system in MPa rounded off to two decimal places?

Mechanical

4.5 TO 4.8

82

G-META-18-55

NUM

48

The ideal plastic work involved in extruding a cylindrical billet of length 100 mm, from an initial diameter of 20 mm to a final diameter of 16 mm is?(in J to one decimal place). The flow stress in compression is 40 MPa, and remains constant throughout the process.

Mechanical

555.5 TO 565.5

83

G-META-19-25

NUM

51

A plate of width 100 𝑐𝑚 and thickness 5 𝑐𝑚 is rolled to a thickness of 3 𝑐𝑚. If the entry velocity is 10 $𝑐𝑚.𝑠^(−1)$ , the exit velocity of the plate (in $𝑐𝑚.𝑠^(−1)$ , rounded off to one decimal place) is? Assume no change in the width of the plate

Mechanical

16.0 TO 17.4

84

G-META-19-32

MCQS

46

An aluminium single crystal is loaded in tension along [1 -1 0] axis. Among the following slip systems, the one that will be activated first is? (A) (1 -1 -1)[0 -1 1] (B) (-1 -1 1)[011] (C) (-1 -1 1)[1 -1 0] (D) (-1 -1 1)[101]

Mechanical

A

85