stellalisy/MaScQA · Datasets at Hugging Face

qid stringlengths 11 16	q_type stringclasses 4 values	correct_answer stringlengths 1 30	topic stringclasses 14 values	question stringlengths 44 799
G-XEC-2012-1	MCQS	D	Atomic structure	Which of the following is NOT a Bravais lattice? (A) Simple tetragonal (B) Body centred tetragonal (C) Base centred orthorhombic (D) Face centred tetragonal
G-XEC-2012-2	MCQS	C	Atomic structure	A Schottky defect in an ionic crystal is a stochiometric defect of (A) Cation vacancy (B) Anion vacancy (C) Cation and anion vacancy (D) Cation and anion interstitial
G-XEC-2012-3	MCQS	A	Thermodynamics	Which of the following techniques is NOT used to grow single crystals of semiconductors? (A) Calendering (B) Czochralski (C) Float zone (D) Bridgman
G-XEC-2012-4	MCQS	B	Thermodynamics	Which of the following signals is produced due to the elastic scattering of electrons by a material? (A) Secondary electron (B) Backscattered electron (C) Auger electron (D) Photoelectron
G-XEC-2012-5	MCQS	A	Magnetism	The best magnetostrictive material is (A) $Nd_2Fe_(14)B$ (B) $Fe_3O_4$ (C) $Cu_2MnAl$ (D) $ZnFe_2O_4$
G-XEC-2012-6	MCQS	C	Thermodynamics	Of the following materials, which is the most suitable for an LED emitting at around 380 nm? (A) Direct bandgap material with a small bandgap (B) Indirect bandgap material with a large bandgap (C) Direct bandgap material with a large bandgap (D) Indirect bandgap material with a small bandgap
G-XEC-2012-7	MCQS	B	Thermodynamics	Which material has the lowest specific heat capacity at room temperature? (A) Water (B) Mercury (C) Copper (D) Silver
G-XEC-2012-8	MCQS	D	Material characterization	Microstrain can be measured by X-ray diffraction using peak (A) Area and intensity (B) Position and area (C) Broadening and intensity (D) Position and broadening
G-XEC-2012-9	MCQS	A	Material Applications	The Pilling-Bedworth ratio is defined as the ratio of (A) Volume of oxide to volume of metal (B) Weight of oxide to weight of metal (C) Density of oxide to density of metal (D) Surface area of oxide to surface area of metal
G-XEC-2012-10	MATCH	B	Miscellaneous	Match the properties in Column I with the appropriate units in Column II: Column I: [P. Thermal diffusivity, Q. Fracture toughness, R. Surface energy, S. Magnetic permeability] Column II: [1. Hm–1, 2. m2s–1, 3. Fm–1, 4. Nm–3/2, 5. Jm–2] Options: (A) P-2, Q-5, R-4, S-1 (B) P-2, Q-4, R-5, S-1 (C) P-3, Q-5, R-4, S-3 (D) P-5, Q-4, R-2, S-3
G-XEC-2012-11	MATCH	A	Material characterization	Match the characterization techniques in Column I with the options in Column II: Column I : [P.Scanning tunneling microscopy, Q. Scanning electron microscopy, R. Transmission electron microscopy, S. Atomic force microscopy] Column II : [1. No vacuum required, 2. Backscattered electrons, 3. Photoelectrons, 4. Atomically sharp tip, 5. Sub-Angstrom resolution] Options: (A) P-4, Q-2, R-5, S-1 (B) P-1, Q-3, R-4, S-5 (C) P-2, Q-4, R-1, S-5 (D) P-5, Q-1, R-2, S-4
G-XEC-2012-12	MATCH	D	Material Applications	Match the materials in Column I with the applications in Column II: Column I : [P. Titanium diboride, Q. Molybdenum disilicide, R. Hydroxyapatite, S. Nanocrystalline titanium oxide] Column II : [1. Photocatalyst, 2. Furnace heating element, 3. Ultra high temperature material, 4. Tough ceramic, 5. Artificial bone implant] Options: (A) P-3, Q-4, R-5, S-1 (B) P-5, Q-3, R-2, S-1 (C) P-4, Q-3, R-1, S-5 (D) P-3, Q-2, R-5, S-1
G-XEC-2012-13	MATCH	C	Mechanical	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
G-XEC-2012-14	MCQS-NUM	D	Material Applications	Determine the mole fraction of vinyl chloride in a copolymer of vinyl chloride ($CH_2CHCl$) and vinyl acetate ($CH_2-CH-OCOCH_3$) having molecular weight of 10520 g/mol and degree of polymerization of 160. (A) 0.14 (B) 0.30 (C) 0.70 (D) 0.86
G-XEC-2012-15	MCQS-NUM	B	Electrical	The electron concentration in an n-type semiconductor is 5 * $1018/m^3$. If the drift velocity of electrons is 100 m/s in an electric field of 500 V/m, calculate the conductivity of the semiconductor. (A) 0.16 * $10^(–1)$ S/m (B) 1.60 * $10^(–1)$ S/m (C) 2.50 * $10^(–1)$ S/m (D) 30.05 * $10^(–1)$ S/m
G-XEC-2012-17	MCQS-NUM	A	Phase transition	A plain 0.45 wt.% carbon steel is cooled slowly from 900°C to just below the eutectoid temperature (723°C) so that the following reaction occurs: γ (0.8 wt.% C) ↔ α (0.02 wt.% C) + $Fe_3C$ (6.67 wt.% C). During cooling from 900°C to 723°C, the proeutectoid α forms from γ. Find the volume % of proeutectoid α just below 723°C for the steel. (A) 44.9% (B) 66.1% (C) 55.1% (D) 34.9%
G-XEC-2012-19	MCQS-NUM	D	Mechanical	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 $cm^2$
G-XEC-2012-21	MCQS-NUM	B	Atomic structure	Chromium has the bcc structure with atomic diameter of 2.494 Å. Calculate the lattice parameter of chromium assuming tight atomic bonding. (A) 1.442 Å (B) 2.880 Å (C) 4.323 Å (D) 5.764 Å
G-XEC-2012-22	MCQS-NUM	C	Atomic structure	Chromium has the bcc structure with atomic diameter of 2.494 Å. Find the first diffraction peak position (2θ) for Cu Kα radiation with a wavelength of 1.54 Å (A) 21.76° (B) 33.05° (C) 44.43° (D) 66.10°
G-XEC-2013-1	MCQS	A	Transport phenomena	As temperature increases, diffusivity of an atom in a solid material, (A) increases (B) decreases (C) remains constant (D) depends on the specific material
G-XEC-2013-2	MCQS	D	Atomic structure	Which of the following is NOT correct? (A) Dislocations are thermodynamically unstable defects. (B) Dislocations can move inside a crystal under the action of an applied stress. (C) Screw dislocations can change the slip plane without climb (D) Burger’s vector of an edge dislocation is parallel to the dislocation line.
G-XEC-2013-3	MCQS	C	Phase transition	At a constant atmospheric pressure, the number of phases, P which coexist in a chosen system at equilibrium, is related to the number of components, C in the system and the degree of freedom, F by (A) P+F=C-2 (B) P+F=C+2 (C) P+F=C+1 (D) P+F=C-1
G-XEC-2013-4	MCQS	B	Material Applications	Which one of the following metals is commonly alloyed with iron to improve its corrosion resistance? (A) Co (B) Cr (C) Ti (D) Nb
G-XEC-2013-5	MCQS	D	Atomic structure	The number of slip systems in a metal with FCC crystal structure is (A) 4 (B) 6 (C) 8 (D) 12
G-XEC-2013-6	MCQS	B	Material processing	Upon recrystallization of a cold worked metal, (A) strength increases and ductility decreases (B)strength decreases but ductility increases (C)both strength and ductility increase (D)both strength and ductility decrease
G-XEC-2013-7	MCQS	B	Material Applications	In carbon fiber reinforced resin composites, for a given fiber volume content, Young’s modulus depends on the orientation of the fiber with respect to the applied load. Which orientation of the fibers will give the maximum value of Young’s modulus? (A)transverse (B)longitudinal (C)random (D)both transverse and longitudinal
G-XEC-2013-8	MCQS	A	Material processing	Vulcanization is related to (A)strengthening of rubber (B)extrusion (C)injection moulding (D)addition polymerisation
G-XEC-2013-9	MCQS	A	Atomic structure	Which one of the following oxides crystallizes into fluorite structure? (A) $UO_2$ (B) MgO (C) $BaTiO_3$ (D) $MgAl_2O_4$
G-XEC-2013-10	MATCH	D	Material Applications	Match the conventional ceramic materials listed in Column I with their respective common applications in Column II: Coloumn I: [P. Lead Zirconate Titanate (PZT), Q. Zinc Oxide (ZnO), R. Silicon Carbide (SiC), S. Zirconia ($ZrO_2$)] Coloumn II: [1. cutting tool, 2. thermal barrier coating, 3. actuator, 4. varistor, 5. super conductor] Options: (A) P-1, Q-2, R-3, S-5 (B) P-3, Q-2, R-1, S-5 (C) P-2, Q-1, R-5, S-3 (D) P-3, Q-4, R-1, S-2
G-XEC-2013-11	MATCH	C	Miscellaneous	Match the terminologies given in Column I with their relations listed in Column II: Column I: [P. domain wall, Q. Fick’s law, R. Matthiessen’s rule, S. Hall-Petch relation, T. Meissner effect] Column II: [1. superconductors, 2. mechanical properties, 3. ferromagnetic materials, 4. resistivity of impure metals, 5. diffusion] Options: (A) P-1, Q-3, R-5, S-2, T-4 (B) P-3, Q-5, R-2, S-4, T-1 (C) P-3, Q- 5, R-4, S-2, T-1 (D) P-3, Q-4, R-3, S-2, T-4
G-XEC-2013-12	MATCH	C	Material characterization	Match the microscopes listed in Column I with their principle of operation listed in Column II: Coloumn I: [P. Scanning Electron Microscope (SEM), Q. Transmission Electron Microscope(TEM), R. Scanning Tunnelling Microscope (STM), S. Atomic Force Microscope (AFM)] Coloumn II: [1. van der Waals forces between atoms, 2. electrons to jump across a potential barrier, 3. diffraction of electrons, 4. detection of secondary electrons, 5. photo emission of electrons] Options: (A) P-2, Q-5, R-3, S-1 (B) P-3, Q-4, R-5, S-2 (C) P-4, Q-3, R-2, S-1 (D) P-4, Q-3, R-5, S-2
G-XEC-2013-15	NUM	0.85 to 0.89	Thermodynamics	The band gap of a semiconducting material used to make an LED is 1.43 eV. What will be the minimum wavelength ofthe radiation emitted by this LED, in μm?
G-XEC-2014-1	MCQS	C	Material Applications	Neoprene is rendered non-inflammable because (A) it has a highly cross-linked structure (B) it has a highly linear chain structure (C) of the presence of chlorine atom in the structure (D) of the absence of chlorine atom in the structure
G-XEC-2014-2	MCQS	A	Material Applications	Nylon-6 is manufactured from (A) caprolactum (B) adipic acid and hexamethylene diamine (C) maleic anhydride and hexamethylene diamine (D) sebasic acid and hexamethylene diamine
G-XEC-2014-3	MCQS	C	Thermodynamics	At room temperature, the typical barrier potential for silicon p-n junction in Volt (V) is (A) 0.7 * $10^(-23)$ (B) 0.07 (C) 0.70 (D) 7.0
G-XEC-2014-4	MCQS	D	Material characterization	Quantitative measurement of the roughness of a polysilicon wafer can be performed with (A) scanning tunneling microscopy (B) scanning electron microscopy (C) transmission electron microscopy (D) atomic force microscopy
G-XEC-2014-5	MCQS	C	Magnetism	The temperature of the antiferromagnetic-to-paramagnetic transition is called (A) Curie temperature (B) Curie-Weiss temperature (C) Neel temperature (D) Debye temperature
G-XEC-2014-6	MCQS	D	Thermodynamics	At low injection level, a forward biased p-n junction would have (A) no charge carriers (B) minority carrier concentration much more than majority carrier concentration (C) minority carrier concentration equal to majority carrier concentration (D) minority carrier concentration much less than majority carrier concentration
G-XEC-2014-7	MCQS	B	Mechanical	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
G-XEC-2014-8	MCQS	A	Atomic structure	The equilibrium concentration of vacancies in a pure metal (A) increases exponentially with temperature (B) decreases exponentially with temperature (C) varies linearly with temperature (D) is independent of temperature
G-XEC-2014-9	MCQS	B	Material Applications	The materials belonging to which one of the following crystal classes would be both piezoelectric and ferroelectric (A) 222 (B) 4mm (C) -1 (D) 2/m
G-XEC-2014-10	NUM	5555 to 5556	Material Applications	Polymerized isotactic polybutadiene has a molecular weight of 3 x $10^5$ g/mol. The degree of polymerization is
G-XEC-2014-12	NUM	48 to 49	Thermodynamics	A copper cup weighing 140 g contains 80 g of water at 4 °C. Specific heats of water and copper are 4.18 and 0.385 J/g °C, respectively. If 100 g of water that is at 90 °C is added to the cup, the final temperature of water in °C is
G-XEC-2014-13	MATCH	B	Phase transition	Match the reaction in Column I with its name in Column II. L – liquid, α, β, γ – different solid solution phases : Coloumn I : [(P) L on cooling gives α + β, (Q) L + β on cooling gives γ, (R) α on cooling gives β] Coloumn II: [(1) peritectic, (2) eutectic, (3) monotectic, (4) eutectoid] Options: (A) P-1, Q-4, R-3 (B) P-2, Q-1, R-4 (C) P-2, Q-3, R-1 (D) P-4, Q-2, R-3
G-XEC-2014-14	NUM	0.29 to 0.31	Mechanical	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
G-XEC-2014-15	MATCH	C	Material Applications	Match the composite in Column I with the most suitable application in Column II. Column I : [(P) Glass fibre reinforced plastic, (Q) SiC particle reinforced Al alloy, (R) Carbon-carbon composite, (S) Metal fibre reinforced rubber] Column II: [(1) Missile cone heads, (2) Commercial automobile chasis, (3) Airplane wheel tyres, (4) Car piston rings, (5) High performance skate boards] Options: (A) P-4, Q-5, R-1, S-2 (B) P-3, Q-5, R-2, S-4 (C) P-5, Q-4, R-1, S-3 (D) P-4, Q-2, R-3, S-1
G-XEC-2014-16	MCQS	A	Phase transition	Which among the following rules need to be satisfied for obtaining an isomorphous phase diagram in a binary alloy system? (P) The atomic size difference should be less than 15%. (Q) Both the end components should have the same crystal structure (R) The valency of the end components should be the same. (S) The end components should have dissimilar electronegativities Options: (A) P, Q, R (B) Q, R, S (C) R, S, P (D) S, P, Q
G-XEC-2014-17	MCQS-NUM	D	Thermodynamics	The energy in eV and the wavelength in μm, respectively, of the photon emitted when an electron in a hydrogen atom falls from n = 4 to n = 2 state is (A) 3.0, 0.413 (B) 2.55, 0.365 (C) 2.75, 0.451 (D) 2.55, 0.487
G-XEC-2014-18	NUM	0.47 to 0.49	Material Applications	Given: ($M_(Ga)$ = 69.72 g/mol; $M_(As)$ = 74.92 g/mol). The weight in kg of gallium (Ga) to be mixed with arsenic (As) for obtaining 1.0 kg of gallium arsenide (GaAs) is
G-XEC-2014-19	MATCH	D	Material Applications	Match the material in Column I with the property in Column II: Coloumn I: [(P) Pb(Zr,Ti)$O_3$, (Q) Ni$_(50)Ti_(50)$, (R) GaAs, (S) $YBa_2Cu_3O_7$] Coloumn II: [(1) Shape memory alloy, (2) Piezoelectric ceramic, (3) High temperature superconductor, (4) Optoelectronic semiconductor] Options: (A) P-1, Q-2, R-3, S-4 (B) P-2, Q-3, R-4, S-1 (C) P-4, Q-1, R-2, S-3 (D) P-2, Q-1, R-4, S-3
G-XEC-2014-21	NUM	40 to 41	Atomic structure	The expected diffraction angle (in degrees) for the first order reflection from the (113) set of planes for face centered cubic Pt (lattice parameter = 0.392 nm) using monochromatic radiation of wavelength 0.1542 nm is
G-XEC-2015-44-1	MCQS	C	Thermodynamics	Arrange the following elements in order of increasing melting point: (P) gallium (Q) tungsten (R) aluminium (S) gold Options: (A) P < R< Q < S (B) S < P < R < Q (C) P < R < S < Q (D) R < S < Q < P
G-XEC-2015-45-2	MCQS	A	Thermodynamics	When the atoms in a solid are separated by their equilibrium distance, (A) the potential energy of the solid is lowest (B) the force of attraction between the atoms is maximum (C) the force of repulsion between the atoms is zero (D) the potential energy of the solid is zero
G-XEC-2015-46-3	MCQS	B	Material Applications	To which of the following category of materials does Teflon (PTFE) belong? (A) Thermosets (B) Thermoplastics (C) Elastomers (D) Block copolymers
G-XEC-2015-47-4	MCQS	D	Thermodynamics	Which of the following statements is TRUE about the glass transition temperature (Tg)? (A) Tg appears below the melting temperature in a perfectly crystalline material (B) Upon heating through Tg, heat capacity remains constant but the thermal expansion coefficient changes (C) Upon heating through Tg, heat capacity changes but the thermal expansion coefficient remains the same (D) Upon heating through Tg, both the heat capacity and thermal expansion coefficient change
G-XEC-2015-48-5	MCQS	B	Thermodynamics	The slope of a graph of $log_e$(conductivity) versus 1/T (where T is the temperature) for an intrinsic semiconductor with energy gap $E_g$, is (A) $E_g$/2k (B) –$E_g$/2k (C) $E_g$/k (D) −$E_g$/k
G-XEC-2015-49-6	MCQS	C	Material manufacturing	Which is NOT a ceramic forming process? (A) extrusion (B) slip casting (C) forging (D) tape casting
G-XEC-2015-50-7	MCQS	D	Magnetism	Which of the following is NOT a soft magnetic material? (A) Iron-silicon steel (B) Nickel zinc ferrite (C) Nickel iron alloy (D) Alnico
G-XEC-2015-51-8	MCQS	B	Phase transition	The eutectic reaction is [Note: S – solid; L− liquid] (A) S1 ⇔ S2 + S3 (B) L ⇔ S1 + S2 (C) L1 + S1 ⇔ L2 + S2 (D) L1 + S1 ⇔ S2 + S3
G-XEC-2015-52-9	MCQS	B	Atomic structure	Vacancies play an important role in (A) deformation twinning (B) self diffusion (C) strain hardening (D) cross-slip
G-XEC-2015-53-10	MATCH	C	Material characterization	Match the techniques listed in Column I with the characteristics of the materials measured in Column II. Coloumn I : [P. DSC, Q. XRD, R. STM, S. SEM] Coloumn II: [1. Density of states, 2. Glass transition temperature, 3. Cathodoluminescence, 4. Crystal structure, 5. Thermal expansion coefficient] Options: (A) P-2, Q-3, R-4, S-1 (B) P-5, Q-4, R-5, S-1 (C) P-2, Q-4, R-1, S-3 (D) P-3, Q-5, R-4, S-2
G-XEC-2015-55-12	NUM	151 to 152	Thermodynamics	With increasing temperature from 15°C in winter to 45°C in summer, the length of an iron rail track increases by 0.05 cm. Calculate the original length of the iron rail track in cm. (linear thermal expansion coefficient of iron is 11.0 * $10^(-6)$ $K^(-1)$)
G-XEC-2015-57-14	NUM	1.5 to 1.55	Electrical	A 1 kg sacrificial anode of Mg (atomic weight: 24.31 amu) is attached to the base of a ship. If the anode lasts for 60 days, what is the average corrosion current (in Amperes) during that period?
G-XEC-2015-59-16	NUM	2 to 2.3	Material Applications	A hot pressed ceramic composite material consists of 30 volume % SiC whiskers in an $Al_2O_3$ matrix. The measured bulk density of this composite is 3.65 g $cm^(-3)$. If the theoretical density of SiC is 3.22 g $cm^(-3)$ and that of $Al_2O_3$ is 3.95 g $cm^(-3)$, estimate the porosity (%) of the composite, assuming that the linear rule of mixtures is valid in this case.
G-XEC-2015-60-17	MATCH	B	Material Applications	Match the technical ceramics listed in Column I with their common applications listed in Column II: Coloumn I: [P. Y-doped $ZrO_2$, Q. $UO_2$, R. $Si_3N_4$, S. AlN, T. Cr doped $Al_2O_3$] Coloumn II: [1. Lasers, 2. Turbine engine, 3. Integrated circuit substrate, 4. Oxygen sensor, 5. Nuclear fuel, 6. Thermistor] Options: (A) P-6, Q-4, R-5, S-1, T-3 (B) P-4, Q-5, R-2, S-3, T-1 (C) P-3, Q-1, R-2, S-6, T-5 (D) P-1, Q-4, R-5, S-2, T-1
G-XEC-2015-61-18	MCQS	D	Mechanical	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)
G-XEC-2015-62-19	MCQS-NUM	B	Atomic structure	Calculate the planar density of the (100) plane in an fcc crystal given that R is the atomic radius of the element. (A) 0.25 $R^2$ (B) 0.25/$R^2$ (C) 1/$R^2$ (D) 4/$R^2$
G-XEC-2015-63-20	NUM	588 to 592	Transport phenomena	The diffusion coefficient of copper atoms in aluminium is found to be 1.28 x $10^(-22)$ $m^2s^(-1)$ at T=400K and 5.75 x $10^(-19)$ $m^2s^(-1)$ at T=500K. Find the temperature (in Kelvin) at which the value of the diffusion coefficient is $10^(-16)$ $m^2s^(-1)$
G-XEC-2015-64-21	NUM	8675 to 8680	Atomic structure	Calculate the density of copper in kg $m^(-3)$ given that copper has an fcc lattice with a lattice parameter of 0.365 nm. Copper has an atomic weight of 63.54 amu
G-XEC-2015-65-22	NUM	1399 to 1401	Thermodynamics	What would be the maximum number of electron-hole pairs that can be generated using a silicon detector irradiated by x-ray of energy 1.54 keV. The band gap of silicon is 1.1 eV.
G-XEC-2016-1	MCQS	C	Material characterization	Energy Dispersive Spectroscopy (EDS) in a typical scanning electron microscope enables elemental identification by collecting and examining which of the following: (A) Secondary electrons from the sample (B) Back scattered electrons from the sample (C) Characteristic X-rays from the sample (D) Diffraction pattern from the sample
G-XEC-2016-2	MCQS	C	Atomic structure	Which of the following rotational symmetry is forbidden in a perfectly periodic 3-dimensional lattice? (A) 1-fold (B) 3-fold (C) 5-fold (D) 6-fold
G-XEC-2016-3	MCQS	D	Thermodynamics	Which of the following thermodynamic properties shows a discontinuity during a second-order phase transition? (A) Volume (B) Enthalpy (C) Entropy (D) Heat capacity
G-XEC-2016-5	MCQS	C	Thermodynamics	For a typical metal at room temperature and atmospheric pressure, the Fermi energy is defined as the energy level for which the probability of occupancy is: (A) 0 (B) 0.25 (C) 0.5 (D) 1
G-XEC-2016-7	MCQS	B	Electrical	Which one of the following effects is the working principle of a thermocouple? (A) Thomson (B) Seebeck (C) Peltier (D) Meissner
G-XEC-2016-8	NUM	4	Phase transition	At equilibrium, the maximum number of phases that can coexist in a ternary system at constant pressure is
G-XEC-2016-9	MCQS	B	Material Applications	Defect-free single crystal alumina (sapphire) is (A) opaque and white. (B) transparent. (C) translucent. (D) opaque and black.
G-XEC-2016-10	MATCH	B	Material manufacturing	Match the following processes and the products obtained: Coloumn I : [P: Mechanical attrition, Q: Physical vapour deposition, R: Injection moulding, S: Sintering] COloumn II : [1: Thin films, 2: Plastics, 3: Nanoparticles, 4: Rails, 5: Carbide tools] Options: (A) P-1, Q-2, R-3, S-5 (B) P-3, Q-1, R-2, S-5 (C) P-4, Q-1, R-3, S-2 (D) P-3, Q-4, R-1, S-2
G-XEC-2016-11	NUM	15.35 : 15.45	Atomic structure	In a diffraction experiment, monochromatic X-rays of wavelength 1.54 Å are used to examine a material with a BCC structure. If the lattice parameter is 4.1 Å, the angular position θ of the first diffraction peak(in degrees) is
G-XEC-2016-12	NUM	210 : 210	Mechanical	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 ?
G-XEC-2016-13	NUM	6850 : 6950	Thermodynamics	Given: Planck’s constant, h = 6.626 * $10^(−34)$ J s, the charge of an electron, e = 1.6 * $10^(−19)$ C, and speed of light, c = 3 * $10^8$ m $s^(−1)$. A direct bandgap semiconductor has a bandgap of 1.8 eV. The threshold value of the wavelength(in Å) BELOW which this material will absorb radiation is
G-XEC-2016-14	NUM	6.00 : 7.30	Electrical	(Given: Universal gas constant, R = 8.31 J $mol^(−1)K^(−1)$, Faraday’s constant, F = 96500 C $mol^(−1)$). A half cell consisting of pure Ni immersed in an aqueous solution containing $Ni^(2+)$ ions of unknown concentration, is galvanically coupled with another half cell consisting of pure Cd immersed in a 1M aqueous solution of $Cd^(2+)$ ions. The temperature is 25°C and pressure is 1 atm. The standard electrode reduction potentials of Ni and Cd are −0.250 V and −0.403 V, respectively. The voltage of the cell is found to be zero. The concentration(in micro molar) of $Ni^(2+)$ in the solution is
G-XEC-2016-15	MATCH	A	Magnetism	Match the type of magnetism given in Group 1 with the material given in Group 2: Group 1 : [P: Ferromagnetic, Q: Ferrimagnetic, R: Antiferromagnetic, S: Paramagnetic] Group 2 : [1: Nickel oxide, 2: Sodium, 3: Magnetite, 4: Cobalt] Options: (A) P-4, Q-3, R-1, S-2 (B) P-4, Q-1, R-3, S-2 (C) P-1, Q-2, R-4, S-3 (D) P-3, Q-2, R-1, S-4
G-XEC-2016-19	NUM	42 TO 43	Material manufacturing	(Given: atomic weight of S is 32 amu and molecular weight of a mer of natural rubber is 68 amu). In the vulcanization of 50 g of natural rubber, 10 g of sulfur is added. Assuming the mer to S ratio is 1:1, the maximum percentage of cross-linked sites that could be connected is
G-XEC-2016-20	MATCH	A	Phase transition	Match the heat treatment process of steels given in Group 1 with the microstructural feature given in Group 2: Group 1 : [P: Quenching, Q: Normalizing, R: Tempering, S: Austempering] Group 2 : [1: Bainite, 2: Martensite, 3: Pearlite, 4: Iron carbide precipitates, 5: Intermetallic precipitates] Options: (A) P-2, Q-3, R-4, S-1 (B) P-3, Q-4, R-5, S-1 (C) P-4, Q-1, R-5, S-3 (D) P-2, Q-5, R-4, S-3
G-XEC-2016-21	MCQS	C	Thermodynamics	In the photoelectric effect, electrons are ejected (A) at all wavelengths, as long as the intensity of the incident radiation is above a threshold value. (B) at all wavelengths, as long as the intensity of the incident radiation is below a threshold value. (C) at all intensities, as long as the wavelength of the incident radiation is below a threshold value. (D) at all intensities, as long as the wavelength of the incident radiation is above a threshold value
G-XEC-2016-22	NUM	35 TO 36	Atomic structure	The angle (in degrees) between [110] and [111] directions in the cubic system is
G-XEC-2017-1	MCQS	B	Atomic structure	Which of the following is a Frenkel defect? (A) One Cl vacancy and one Na vacancy in NaCl (B) One Zn vacancy and one Zn interstitial in ZnO (C) K at the Na site in NaCl (D) None of the above
G-XEC-2017-2	MCQS	D	Material Applications	Which processing technique is best suited for manufacturing decorative PVC floor tiles? (A) Blow molding (B) Filament winding(C) Rotational molding (D) Calendering
G-XEC-2017-3	MCQS	C	Atomic structure	During deformation of a semi-crystalline polymer, with spherulitic morphology, stressed in tension. what happens to the amorphous and the crystalline regions at the later stages? (A) Amorphous regions remain intact and only crystallites experience bending and stretching of chains (B) Only amorphous regions elongate in the stress direction and crystallites remain intact (C) Amorphous regions elongate in the stress direction and crystallites experience bending and stretching of chains (D) None of the above
G-XEC-2017-4	MCQS	B	Atomic structure	Which of the following statement (s) is / are true regarding the structure-property correlation in polymers? (i) Polymers that are less coiled are more crystalline than those that are more coiled (ii) Branched polymers are more crystalline than the linear ones (iii)Polymers with inter-chain interactions have higher glass transition temperature than those without inter-chain interactions (iv) Polymers with inter-chain interactions are more crystalline than those without inter-chain interactions (A) (i) and (ii) (B) (i) and (iii) (C) (ii) and (iv) (D) (ii) and (iii)
G-XEC-2017-5	MCQS	A	Material characterization	The contrast obtained in scanning electron microscope using back scattered electrons depends on (A) Atomic number of the specimen material (B) Accelerating voltage of the microscope (C) Working distance in the microscope (D) Type of the electron emitter in the microscope
G-XEC-2017-6	MCQS	C	Mechanical	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
G-XEC-2017-7	MCQS	D	Atomic structure	The Miller indices of the first three Bragg peaks in the X-ray diffraction pattern obtained from a polycrystalline iron sample at room temperature are (A) (111), (200), (220) (B) (100), (110), (111) (C) (100), (110), (200) (D) (110), (200), (220)
G-XEC-2017-9	MCQS	D	Electrical	Which of the following treatment(s) can increase the electrical conductivity of silicon- (i) Heating (ii) Doping with arsenic (iii) Doping with aluminium (iv) Exposure to light Options: (A) Only (i) (B) Only (i) and (ii) (C) Only (i), (ii) and (iv) (D) All (i), (ii), (iii) and (iv)
G-XEC-2017-10	NUM	0.99 to 1.010	Material Applications	The unit cell volume of polyethylene (PE) is 0.0933 $nm^3$. Assuming two ethylene repeat units are contained within each unit cell, the density(in g/ $cm^3$) of a totally crystalline PE will be? (Take the atomic weights for carbon and hydrogen as 12.01 g/mol and 1.008 g/mol, respectively and the avogadro's number as 6.023* $10^(23)$ repeat units/mol)
G-XEC-2017-11	NUM	53 to 53.2	Mechanical	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
G-XEC-2017-12	MATCH	A	Material Applications	Match the composites in column I with the most suitable application in Coloumn II: Coloumn I: [(P) Exfoliated silicates filled butyl rubber, (Q) Fiber reinforced aluminium alloy, (R)Silicon carbide whiskers reinforced alumina, (S) carbon particles reinforced plastic composites] Coloumn II: [(1) Automobile pistons, (2) Contact lenses, (3) Ski boards, (4) Tennis balls, (5) Cutting tool inserts for machining] Options: (A) P-4; Q-1; R-5; S-3 (B) P-2; Q-3; R-4; S-5 (C) P-3; Q-5; R-5; S-3 (D) P-2; Q-1; R-3; S-5
G-XEC-2017-13	MATCH	A	Material processing	Match the processes in Coloumn type I with products in Coloumn II: Coloumn I: [(P) Slip casting, (Q) Zone refining, (R)Sputtering, (S) Atomization] Coloumn II: [(1) Metal powders, (2) Thin films, (3) Ceramic parts, (4) Single crystal, (5) Metal sheets] Options: (A) P-3; Q-4; R-2; S-1 (B) P-2; Q-1; R-2; S-1 (C) P-3; Q-4; R-5; S-1 (D) P-3; Q-4; R-1; S-5
G-XEC-2017-16	MCQS	B	Miscellaneous	Which of the following statement(s) is/are true: (i) All piezoelectric materials are necessarily ferroelectric (ii) All ferroelectric materials are necessarily piezoelectric (iii) All pyroelectric materials are necessarily piezoelectric (iv) All pyroelectric materials are necessarily ferroelectric (A) (i) and (ii) (B) (ii) and (iii) (C) (i) and (iv) (D) (ii) and (iv)

G-XEC-2012-1

MCQS

D

Atomic structure

Which of the following is NOT a Bravais lattice? (A) Simple tetragonal (B) Body centred tetragonal (C) Base centred orthorhombic (D) Face centred tetragonal

G-XEC-2012-2

MCQS

C

Atomic structure

A Schottky defect in an ionic crystal is a stochiometric defect of (A) Cation vacancy (B) Anion vacancy (C) Cation and anion vacancy (D) Cation and anion interstitial

G-XEC-2012-3

MCQS

A

Thermodynamics

Which of the following techniques is NOT used to grow single crystals of semiconductors? (A) Calendering (B) Czochralski (C) Float zone (D) Bridgman

G-XEC-2012-4

MCQS

B

Thermodynamics

Which of the following signals is produced due to the elastic scattering of electrons by a material? (A) Secondary electron (B) Backscattered electron (C) Auger electron (D) Photoelectron

G-XEC-2012-5

MCQS

A

Magnetism

The best magnetostrictive material is (A) $Nd_2Fe_(14)B$ (B) $Fe_3O_4$ (C) $Cu_2MnAl$ (D) $ZnFe_2O_4$

G-XEC-2012-6

MCQS

C

Thermodynamics

Of the following materials, which is the most suitable for an LED emitting at around 380 nm? (A) Direct bandgap material with a small bandgap (B) Indirect bandgap material with a large bandgap (C) Direct bandgap material with a large bandgap (D) Indirect bandgap material with a small bandgap

G-XEC-2012-7

MCQS

B

Thermodynamics

Which material has the lowest specific heat capacity at room temperature? (A) Water (B) Mercury (C) Copper (D) Silver

G-XEC-2012-8

MCQS

D

Material characterization

Microstrain can be measured by X-ray diffraction using peak (A) Area and intensity (B) Position and area (C) Broadening and intensity (D) Position and broadening

G-XEC-2012-9

MCQS

A

Material Applications

The Pilling-Bedworth ratio is defined as the ratio of (A) Volume of oxide to volume of metal (B) Weight of oxide to weight of metal (C) Density of oxide to density of metal (D) Surface area of oxide to surface area of metal

G-XEC-2012-10

MATCH

B

Miscellaneous

Match the properties in Column I with the appropriate units in Column II: Column I: [P. Thermal diffusivity, Q. Fracture toughness, R. Surface energy, S. Magnetic permeability] Column II: [1. Hm–1, 2. m2s–1, 3. Fm–1, 4. Nm–3/2, 5. Jm–2] Options: (A) P-2, Q-5, R-4, S-1 (B) P-2, Q-4, R-5, S-1 (C) P-3, Q-5, R-4, S-3 (D) P-5, Q-4, R-2, S-3

G-XEC-2012-11

MATCH

A

Material characterization

Match the characterization techniques in Column I with the options in Column II: Column I : [P.Scanning tunneling microscopy, Q. Scanning electron microscopy, R. Transmission electron microscopy, S. Atomic force microscopy] Column II : [1. No vacuum required, 2. Backscattered electrons, 3. Photoelectrons, 4. Atomically sharp tip, 5. Sub-Angstrom resolution] Options: (A) P-4, Q-2, R-5, S-1 (B) P-1, Q-3, R-4, S-5 (C) P-2, Q-4, R-1, S-5 (D) P-5, Q-1, R-2, S-4

G-XEC-2012-12

MATCH

D

Material Applications

Match the materials in Column I with the applications in Column II: Column I : [P. Titanium diboride, Q. Molybdenum disilicide, R. Hydroxyapatite, S. Nanocrystalline titanium oxide] Column II : [1. Photocatalyst, 2. Furnace heating element, 3. Ultra high temperature material, 4. Tough ceramic, 5. Artificial bone implant] Options: (A) P-3, Q-4, R-5, S-1 (B) P-5, Q-3, R-2, S-1 (C) P-4, Q-3, R-1, S-5 (D) P-3, Q-2, R-5, S-1

G-XEC-2012-13

MATCH

C

Mechanical

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

G-XEC-2012-14

MCQS-NUM

D

Material Applications

Determine the mole fraction of vinyl chloride in a copolymer of vinyl chloride ($CH_2CHCl$) and vinyl acetate ($CH_2-CH-OCOCH_3$) having molecular weight of 10520 g/mol and degree of polymerization of 160. (A) 0.14 (B) 0.30 (C) 0.70 (D) 0.86

G-XEC-2012-15

MCQS-NUM

B

Electrical

The electron concentration in an n-type semiconductor is 5 * $1018/m^3$. If the drift velocity of electrons is 100 m/s in an electric field of 500 V/m, calculate the conductivity of the semiconductor. (A) 0.16 * $10^(–1)$ S/m (B) 1.60 * $10^(–1)$ S/m (C) 2.50 * $10^(–1)$ S/m (D) 30.05 * $10^(–1)$ S/m

G-XEC-2012-17

MCQS-NUM

A

Phase transition

A plain 0.45 wt.% carbon steel is cooled slowly from 900°C to just below the eutectoid temperature (723°C) so that the following reaction occurs: γ (0.8 wt.% C) ↔ α (0.02 wt.% C) + $Fe_3C$ (6.67 wt.% C). During cooling from 900°C to 723°C, the proeutectoid α forms from γ. Find the volume % of proeutectoid α just below 723°C for the steel. (A) 44.9% (B) 66.1% (C) 55.1% (D) 34.9%

G-XEC-2012-19

MCQS-NUM

D

Mechanical

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 $cm^2$

G-XEC-2012-21

MCQS-NUM

B

Atomic structure

Chromium has the bcc structure with atomic diameter of 2.494 Å. Calculate the lattice parameter of chromium assuming tight atomic bonding. (A) 1.442 Å (B) 2.880 Å (C) 4.323 Å (D) 5.764 Å

G-XEC-2012-22

MCQS-NUM

C

Atomic structure

Chromium has the bcc structure with atomic diameter of 2.494 Å. Find the first diffraction peak position (2θ) for Cu Kα radiation with a wavelength of 1.54 Å (A) 21.76° (B) 33.05° (C) 44.43° (D) 66.10°

G-XEC-2013-1

MCQS

A

Transport phenomena

As temperature increases, diffusivity of an atom in a solid material, (A) increases (B) decreases (C) remains constant (D) depends on the specific material

G-XEC-2013-2

MCQS

D

Atomic structure

Which of the following is NOT correct? (A) Dislocations are thermodynamically unstable defects. (B) Dislocations can move inside a crystal under the action of an applied stress. (C) Screw dislocations can change the slip plane without climb (D) Burger’s vector of an edge dislocation is parallel to the dislocation line.

G-XEC-2013-3

MCQS

C

Phase transition

At a constant atmospheric pressure, the number of phases, P which coexist in a chosen system at equilibrium, is related to the number of components, C in the system and the degree of freedom, F by (A) P+F=C-2 (B) P+F=C+2 (C) P+F=C+1 (D) P+F=C-1

G-XEC-2013-4

MCQS

B

Material Applications

Which one of the following metals is commonly alloyed with iron to improve its corrosion resistance? (A) Co (B) Cr (C) Ti (D) Nb

G-XEC-2013-5

MCQS

D

Atomic structure

The number of slip systems in a metal with FCC crystal structure is (A) 4 (B) 6 (C) 8 (D) 12

G-XEC-2013-6

MCQS

B

Material processing

Upon recrystallization of a cold worked metal, (A) strength increases and ductility decreases (B)strength decreases but ductility increases (C)both strength and ductility increase (D)both strength and ductility decrease

G-XEC-2013-7

MCQS

B

Material Applications

In carbon fiber reinforced resin composites, for a given fiber volume content, Young’s modulus depends on the orientation of the fiber with respect to the applied load. Which orientation of the fibers will give the maximum value of Young’s modulus? (A)transverse (B)longitudinal (C)random (D)both transverse and longitudinal

G-XEC-2013-8

MCQS

A

Material processing

Vulcanization is related to (A)strengthening of rubber (B)extrusion (C)injection moulding (D)addition polymerisation

G-XEC-2013-9

MCQS

A

Atomic structure

Which one of the following oxides crystallizes into fluorite structure? (A) $UO_2$ (B) MgO (C) $BaTiO_3$ (D) $MgAl_2O_4$

G-XEC-2013-10

MATCH

D

Material Applications

Match the conventional ceramic materials listed in Column I with their respective common applications in Column II: Coloumn I: [P. Lead Zirconate Titanate (PZT), Q. Zinc Oxide (ZnO), R. Silicon Carbide (SiC), S. Zirconia ($ZrO_2$)] Coloumn II: [1. cutting tool, 2. thermal barrier coating, 3. actuator, 4. varistor, 5. super conductor] Options: (A) P-1, Q-2, R-3, S-5 (B) P-3, Q-2, R-1, S-5 (C) P-2, Q-1, R-5, S-3 (D) P-3, Q-4, R-1, S-2

G-XEC-2013-11

MATCH

C

Miscellaneous

Match the terminologies given in Column I with their relations listed in Column II: Column I: [P. domain wall, Q. Fick’s law, R. Matthiessen’s rule, S. Hall-Petch relation, T. Meissner effect] Column II: [1. superconductors, 2. mechanical properties, 3. ferromagnetic materials, 4. resistivity of impure metals, 5. diffusion] Options: (A) P-1, Q-3, R-5, S-2, T-4 (B) P-3, Q-5, R-2, S-4, T-1 (C) P-3, Q- 5, R-4, S-2, T-1 (D) P-3, Q-4, R-3, S-2, T-4

G-XEC-2013-12

MATCH

C

Material characterization

Match the microscopes listed in Column I with their principle of operation listed in Column II: Coloumn I: [P. Scanning Electron Microscope (SEM), Q. Transmission Electron Microscope(TEM), R. Scanning Tunnelling Microscope (STM), S. Atomic Force Microscope (AFM)] Coloumn II: [1. van der Waals forces between atoms, 2. electrons to jump across a potential barrier, 3. diffraction of electrons, 4. detection of secondary electrons, 5. photo emission of electrons] Options: (A) P-2, Q-5, R-3, S-1 (B) P-3, Q-4, R-5, S-2 (C) P-4, Q-3, R-2, S-1 (D) P-4, Q-3, R-5, S-2

G-XEC-2013-15

NUM

0.85 to 0.89

Thermodynamics

The band gap of a semiconducting material used to make an LED is 1.43 eV. What will be the minimum wavelength ofthe radiation emitted by this LED, in μm?

G-XEC-2014-1

MCQS

C

Material Applications

Neoprene is rendered non-inflammable because (A) it has a highly cross-linked structure (B) it has a highly linear chain structure (C) of the presence of chlorine atom in the structure (D) of the absence of chlorine atom in the structure

G-XEC-2014-2

MCQS

A

Material Applications

Nylon-6 is manufactured from (A) caprolactum (B) adipic acid and hexamethylene diamine (C) maleic anhydride and hexamethylene diamine (D) sebasic acid and hexamethylene diamine

G-XEC-2014-3

MCQS

C

Thermodynamics

At room temperature, the typical barrier potential for silicon p-n junction in Volt (V) is (A) 0.7 * $10^(-23)$ (B) 0.07 (C) 0.70 (D) 7.0

G-XEC-2014-4

MCQS

D

Material characterization

Quantitative measurement of the roughness of a polysilicon wafer can be performed with (A) scanning tunneling microscopy (B) scanning electron microscopy (C) transmission electron microscopy (D) atomic force microscopy

G-XEC-2014-5

MCQS

C

Magnetism

The temperature of the antiferromagnetic-to-paramagnetic transition is called (A) Curie temperature (B) Curie-Weiss temperature (C) Neel temperature (D) Debye temperature

G-XEC-2014-6

MCQS

D

Thermodynamics

At low injection level, a forward biased p-n junction would have (A) no charge carriers (B) minority carrier concentration much more than majority carrier concentration (C) minority carrier concentration equal to majority carrier concentration (D) minority carrier concentration much less than majority carrier concentration

G-XEC-2014-7

MCQS

B

Mechanical

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

G-XEC-2014-8

MCQS

A

Atomic structure

The equilibrium concentration of vacancies in a pure metal (A) increases exponentially with temperature (B) decreases exponentially with temperature (C) varies linearly with temperature (D) is independent of temperature

G-XEC-2014-9

MCQS

B

Material Applications

The materials belonging to which one of the following crystal classes would be both piezoelectric and ferroelectric (A) 222 (B) 4mm (C) -1 (D) 2/m

G-XEC-2014-10

NUM

5555 to 5556

Material Applications

Polymerized isotactic polybutadiene has a molecular weight of 3 x $10^5$ g/mol. The degree of polymerization is

G-XEC-2014-12

NUM

48 to 49

Thermodynamics

A copper cup weighing 140 g contains 80 g of water at 4 °C. Specific heats of water and copper are 4.18 and 0.385 J/g °C, respectively. If 100 g of water that is at 90 °C is added to the cup, the final temperature of water in °C is

G-XEC-2014-13

MATCH

B

Phase transition

Match the reaction in Column I with its name in Column II. L – liquid, α, β, γ – different solid solution phases : Coloumn I : [(P) L on cooling gives α + β, (Q) L + β on cooling gives γ, (R) α on cooling gives β] Coloumn II: [(1) peritectic, (2) eutectic, (3) monotectic, (4) eutectoid] Options: (A) P-1, Q-4, R-3 (B) P-2, Q-1, R-4 (C) P-2, Q-3, R-1 (D) P-4, Q-2, R-3

G-XEC-2014-14

NUM

0.29 to 0.31

Mechanical

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

G-XEC-2014-15

MATCH

C

Material Applications

Match the composite in Column I with the most suitable application in Column II. Column I : [(P) Glass fibre reinforced plastic, (Q) SiC particle reinforced Al alloy, (R) Carbon-carbon composite, (S) Metal fibre reinforced rubber] Column II: [(1) Missile cone heads, (2) Commercial automobile chasis, (3) Airplane wheel tyres, (4) Car piston rings, (5) High performance skate boards] Options: (A) P-4, Q-5, R-1, S-2 (B) P-3, Q-5, R-2, S-4 (C) P-5, Q-4, R-1, S-3 (D) P-4, Q-2, R-3, S-1

G-XEC-2014-16

MCQS

A

Phase transition

Which among the following rules need to be satisfied for obtaining an isomorphous phase diagram in a binary alloy system? (P) The atomic size difference should be less than 15%. (Q) Both the end components should have the same crystal structure (R) The valency of the end components should be the same. (S) The end components should have dissimilar electronegativities Options: (A) P, Q, R (B) Q, R, S (C) R, S, P (D) S, P, Q

G-XEC-2014-17

MCQS-NUM

D

Thermodynamics

The energy in eV and the wavelength in μm, respectively, of the photon emitted when an electron in a hydrogen atom falls from n = 4 to n = 2 state is (A) 3.0, 0.413 (B) 2.55, 0.365 (C) 2.75, 0.451 (D) 2.55, 0.487

G-XEC-2014-18

NUM

0.47 to 0.49

Material Applications

Given: ($M_(Ga)$ = 69.72 g/mol; $M_(As)$ = 74.92 g/mol). The weight in kg of gallium (Ga) to be mixed with arsenic (As) for obtaining 1.0 kg of gallium arsenide (GaAs) is

G-XEC-2014-19

MATCH

D

Material Applications

Match the material in Column I with the property in Column II: Coloumn I: [(P) Pb(Zr,Ti)$O_3$, (Q) Ni$_(50)Ti_(50)$, (R) GaAs, (S) $YBa_2Cu_3O_7$] Coloumn II: [(1) Shape memory alloy, (2) Piezoelectric ceramic, (3) High temperature superconductor, (4) Optoelectronic semiconductor] Options: (A) P-1, Q-2, R-3, S-4 (B) P-2, Q-3, R-4, S-1 (C) P-4, Q-1, R-2, S-3 (D) P-2, Q-1, R-4, S-3

G-XEC-2014-21

NUM

40 to 41

Atomic structure

The expected diffraction angle (in degrees) for the first order reflection from the (113) set of planes for face centered cubic Pt (lattice parameter = 0.392 nm) using monochromatic radiation of wavelength 0.1542 nm is

G-XEC-2015-44-1

MCQS

C

Thermodynamics

Arrange the following elements in order of increasing melting point: (P) gallium (Q) tungsten (R) aluminium (S) gold Options: (A) P < R< Q < S (B) S < P < R < Q (C) P < R < S < Q (D) R < S < Q < P

G-XEC-2015-45-2

MCQS

A

Thermodynamics

When the atoms in a solid are separated by their equilibrium distance, (A) the potential energy of the solid is lowest (B) the force of attraction between the atoms is maximum (C) the force of repulsion between the atoms is zero (D) the potential energy of the solid is zero

G-XEC-2015-46-3

MCQS

B

Material Applications

To which of the following category of materials does Teflon (PTFE) belong? (A) Thermosets (B) Thermoplastics (C) Elastomers (D) Block copolymers

G-XEC-2015-47-4

MCQS

D

Thermodynamics

Which of the following statements is TRUE about the glass transition temperature (Tg)? (A) Tg appears below the melting temperature in a perfectly crystalline material (B) Upon heating through Tg, heat capacity remains constant but the thermal expansion coefficient changes (C) Upon heating through Tg, heat capacity changes but the thermal expansion coefficient remains the same (D) Upon heating through Tg, both the heat capacity and thermal expansion coefficient change

G-XEC-2015-48-5

MCQS

B

Thermodynamics

The slope of a graph of $log_e$(conductivity) versus 1/T (where T is the temperature) for an intrinsic semiconductor with energy gap $E_g$, is (A) $E_g$/2k (B) –$E_g$/2k (C) $E_g$/k (D) −$E_g$/k

G-XEC-2015-49-6

MCQS

C

Material manufacturing

Which is NOT a ceramic forming process? (A) extrusion (B) slip casting (C) forging (D) tape casting

G-XEC-2015-50-7

MCQS

D

Magnetism

Which of the following is NOT a soft magnetic material? (A) Iron-silicon steel (B) Nickel zinc ferrite (C) Nickel iron alloy (D) Alnico

G-XEC-2015-51-8

MCQS

B

Phase transition

The eutectic reaction is [Note: S – solid; L− liquid] (A) S1 ⇔ S2 + S3 (B) L ⇔ S1 + S2 (C) L1 + S1 ⇔ L2 + S2 (D) L1 + S1 ⇔ S2 + S3

G-XEC-2015-52-9

MCQS

B

Atomic structure

Vacancies play an important role in (A) deformation twinning (B) self diffusion (C) strain hardening (D) cross-slip

G-XEC-2015-53-10

MATCH

C

Material characterization

Match the techniques listed in Column I with the characteristics of the materials measured in Column II. Coloumn I : [P. DSC, Q. XRD, R. STM, S. SEM] Coloumn II: [1. Density of states, 2. Glass transition temperature, 3. Cathodoluminescence, 4. Crystal structure, 5. Thermal expansion coefficient] Options: (A) P-2, Q-3, R-4, S-1 (B) P-5, Q-4, R-5, S-1 (C) P-2, Q-4, R-1, S-3 (D) P-3, Q-5, R-4, S-2

G-XEC-2015-55-12

NUM

151 to 152

Thermodynamics

With increasing temperature from 15°C in winter to 45°C in summer, the length of an iron rail track increases by 0.05 cm. Calculate the original length of the iron rail track in cm. (linear thermal expansion coefficient of iron is 11.0 * $10^(-6)$ $K^(-1)$)

G-XEC-2015-57-14

NUM

1.5 to 1.55

Electrical

A 1 kg sacrificial anode of Mg (atomic weight: 24.31 amu) is attached to the base of a ship. If the anode lasts for 60 days, what is the average corrosion current (in Amperes) during that period?

G-XEC-2015-59-16

NUM

2 to 2.3

Material Applications

A hot pressed ceramic composite material consists of 30 volume % SiC whiskers in an $Al_2O_3$ matrix. The measured bulk density of this composite is 3.65 g $cm^(-3)$. If the theoretical density of SiC is 3.22 g $cm^(-3)$ and that of $Al_2O_3$ is 3.95 g $cm^(-3)$, estimate the porosity (%) of the composite, assuming that the linear rule of mixtures is valid in this case.

G-XEC-2015-60-17

MATCH

B

Material Applications

Match the technical ceramics listed in Column I with their common applications listed in Column II: Coloumn I: [P. Y-doped $ZrO_2$, Q. $UO_2$, R. $Si_3N_4$, S. AlN, T. Cr doped $Al_2O_3$] Coloumn II: [1. Lasers, 2. Turbine engine, 3. Integrated circuit substrate, 4. Oxygen sensor, 5. Nuclear fuel, 6. Thermistor] Options: (A) P-6, Q-4, R-5, S-1, T-3 (B) P-4, Q-5, R-2, S-3, T-1 (C) P-3, Q-1, R-2, S-6, T-5 (D) P-1, Q-4, R-5, S-2, T-1

G-XEC-2015-61-18

MCQS

D

Mechanical

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)

G-XEC-2015-62-19

MCQS-NUM

B

Atomic structure

Calculate the planar density of the (100) plane in an fcc crystal given that R is the atomic radius of the element. (A) 0.25 $R^2$ (B) 0.25/$R^2$ (C) 1/$R^2$ (D) 4/$R^2$

G-XEC-2015-63-20

NUM

588 to 592

Transport phenomena

The diffusion coefficient of copper atoms in aluminium is found to be 1.28 x $10^(-22)$ $m^2s^(-1)$ at T=400K and 5.75 x $10^(-19)$ $m^2s^(-1)$ at T=500K. Find the temperature (in Kelvin) at which the value of the diffusion coefficient is $10^(-16)$ $m^2s^(-1)$

G-XEC-2015-64-21

NUM

8675 to 8680

Atomic structure

Calculate the density of copper in kg $m^(-3)$ given that copper has an fcc lattice with a lattice parameter of 0.365 nm. Copper has an atomic weight of 63.54 amu

G-XEC-2015-65-22

NUM

1399 to 1401

Thermodynamics

What would be the maximum number of electron-hole pairs that can be generated using a silicon detector irradiated by x-ray of energy 1.54 keV. The band gap of silicon is 1.1 eV.

G-XEC-2016-1

MCQS

C

Material characterization

Energy Dispersive Spectroscopy (EDS) in a typical scanning electron microscope enables elemental identification by collecting and examining which of the following: (A) Secondary electrons from the sample (B) Back scattered electrons from the sample (C) Characteristic X-rays from the sample (D) Diffraction pattern from the sample

G-XEC-2016-2

MCQS

C

Atomic structure

Which of the following rotational symmetry is forbidden in a perfectly periodic 3-dimensional lattice? (A) 1-fold (B) 3-fold (C) 5-fold (D) 6-fold

G-XEC-2016-3

MCQS

D

Thermodynamics

Which of the following thermodynamic properties shows a discontinuity during a second-order phase transition? (A) Volume (B) Enthalpy (C) Entropy (D) Heat capacity

G-XEC-2016-5

MCQS

C

Thermodynamics

For a typical metal at room temperature and atmospheric pressure, the Fermi energy is defined as the energy level for which the probability of occupancy is: (A) 0 (B) 0.25 (C) 0.5 (D) 1

G-XEC-2016-7

MCQS

B

Electrical

Which one of the following effects is the working principle of a thermocouple? (A) Thomson (B) Seebeck (C) Peltier (D) Meissner

G-XEC-2016-8

NUM

4

Phase transition

At equilibrium, the maximum number of phases that can coexist in a ternary system at constant pressure is

G-XEC-2016-9

MCQS

B

Material Applications

Defect-free single crystal alumina (sapphire) is (A) opaque and white. (B) transparent. (C) translucent. (D) opaque and black.

G-XEC-2016-10

MATCH

B

Material manufacturing

Match the following processes and the products obtained: Coloumn I : [P: Mechanical attrition, Q: Physical vapour deposition, R: Injection moulding, S: Sintering] COloumn II : [1: Thin films, 2: Plastics, 3: Nanoparticles, 4: Rails, 5: Carbide tools] Options: (A) P-1, Q-2, R-3, S-5 (B) P-3, Q-1, R-2, S-5 (C) P-4, Q-1, R-3, S-2 (D) P-3, Q-4, R-1, S-2

G-XEC-2016-11

NUM

15.35 : 15.45

Atomic structure

In a diffraction experiment, monochromatic X-rays of wavelength 1.54 Å are used to examine a material with a BCC structure. If the lattice parameter is 4.1 Å, the angular position θ of the first diffraction peak(in degrees) is

G-XEC-2016-12

NUM

210 : 210

Mechanical

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 ?

G-XEC-2016-13

NUM

6850 : 6950

Thermodynamics

Given: Planck’s constant, h = 6.626 * $10^(−34)$ J s, the charge of an electron, e = 1.6 * $10^(−19)$ C, and speed of light, c = 3 * $10^8$ m $s^(−1)$. A direct bandgap semiconductor has a bandgap of 1.8 eV. The threshold value of the wavelength(in Å) BELOW which this material will absorb radiation is

G-XEC-2016-14

NUM

6.00 : 7.30

Electrical

(Given: Universal gas constant, R = 8.31 J $mol^(−1)K^(−1)$, Faraday’s constant, F = 96500 C $mol^(−1)$). A half cell consisting of pure Ni immersed in an aqueous solution containing $Ni^(2+)$ ions of unknown concentration, is galvanically coupled with another half cell consisting of pure Cd immersed in a 1M aqueous solution of $Cd^(2+)$ ions. The temperature is 25°C and pressure is 1 atm. The standard electrode reduction potentials of Ni and Cd are −0.250 V and −0.403 V, respectively. The voltage of the cell is found to be zero. The concentration(in micro molar) of $Ni^(2+)$ in the solution is

G-XEC-2016-15

MATCH

A

Magnetism

Match the type of magnetism given in Group 1 with the material given in Group 2: Group 1 : [P: Ferromagnetic, Q: Ferrimagnetic, R: Antiferromagnetic, S: Paramagnetic] Group 2 : [1: Nickel oxide, 2: Sodium, 3: Magnetite, 4: Cobalt] Options: (A) P-4, Q-3, R-1, S-2 (B) P-4, Q-1, R-3, S-2 (C) P-1, Q-2, R-4, S-3 (D) P-3, Q-2, R-1, S-4

G-XEC-2016-19

NUM

42 TO 43

Material manufacturing

(Given: atomic weight of S is 32 amu and molecular weight of a mer of natural rubber is 68 amu). In the vulcanization of 50 g of natural rubber, 10 g of sulfur is added. Assuming the mer to S ratio is 1:1, the maximum percentage of cross-linked sites that could be connected is

G-XEC-2016-20

MATCH

A

Phase transition

Match the heat treatment process of steels given in Group 1 with the microstructural feature given in Group 2: Group 1 : [P: Quenching, Q: Normalizing, R: Tempering, S: Austempering] Group 2 : [1: Bainite, 2: Martensite, 3: Pearlite, 4: Iron carbide precipitates, 5: Intermetallic precipitates] Options: (A) P-2, Q-3, R-4, S-1 (B) P-3, Q-4, R-5, S-1 (C) P-4, Q-1, R-5, S-3 (D) P-2, Q-5, R-4, S-3

G-XEC-2016-21

MCQS

C

Thermodynamics

In the photoelectric effect, electrons are ejected (A) at all wavelengths, as long as the intensity of the incident radiation is above a threshold value. (B) at all wavelengths, as long as the intensity of the incident radiation is below a threshold value. (C) at all intensities, as long as the wavelength of the incident radiation is below a threshold value. (D) at all intensities, as long as the wavelength of the incident radiation is above a threshold value

G-XEC-2016-22

NUM

35 TO 36

Atomic structure

The angle (in degrees) between [110] and [111] directions in the cubic system is

G-XEC-2017-1

MCQS

B

Atomic structure

Which of the following is a Frenkel defect? (A) One Cl vacancy and one Na vacancy in NaCl (B) One Zn vacancy and one Zn interstitial in ZnO (C) K at the Na site in NaCl (D) None of the above

G-XEC-2017-2

MCQS

D

Material Applications

Which processing technique is best suited for manufacturing decorative PVC floor tiles? (A) Blow molding (B) Filament winding(C) Rotational molding (D) Calendering

G-XEC-2017-3

MCQS

C

Atomic structure

During deformation of a semi-crystalline polymer, with spherulitic morphology, stressed in tension. what happens to the amorphous and the crystalline regions at the later stages? (A) Amorphous regions remain intact and only crystallites experience bending and stretching of chains (B) Only amorphous regions elongate in the stress direction and crystallites remain intact (C) Amorphous regions elongate in the stress direction and crystallites experience bending and stretching of chains (D) None of the above

G-XEC-2017-4

MCQS

B

Atomic structure

Which of the following statement (s) is / are true regarding the structure-property correlation in polymers? (i) Polymers that are less coiled are more crystalline than those that are more coiled (ii) Branched polymers are more crystalline than the linear ones (iii)Polymers with inter-chain interactions have higher glass transition temperature than those without inter-chain interactions (iv) Polymers with inter-chain interactions are more crystalline than those without inter-chain interactions (A) (i) and (ii) (B) (i) and (iii) (C) (ii) and (iv) (D) (ii) and (iii)

G-XEC-2017-5

MCQS

A

Material characterization

The contrast obtained in scanning electron microscope using back scattered electrons depends on (A) Atomic number of the specimen material (B) Accelerating voltage of the microscope (C) Working distance in the microscope (D) Type of the electron emitter in the microscope

G-XEC-2017-6

MCQS

C

Mechanical

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

G-XEC-2017-7

MCQS

D

Atomic structure

The Miller indices of the first three Bragg peaks in the X-ray diffraction pattern obtained from a polycrystalline iron sample at room temperature are (A) (111), (200), (220) (B) (100), (110), (111) (C) (100), (110), (200) (D) (110), (200), (220)

G-XEC-2017-9

MCQS

D

Electrical

Which of the following treatment(s) can increase the electrical conductivity of silicon- (i) Heating (ii) Doping with arsenic (iii) Doping with aluminium (iv) Exposure to light Options: (A) Only (i) (B) Only (i) and (ii) (C) Only (i), (ii) and (iv) (D) All (i), (ii), (iii) and (iv)

G-XEC-2017-10

NUM

0.99 to 1.010

Material Applications

The unit cell volume of polyethylene (PE) is 0.0933 $nm^3$. Assuming two ethylene repeat units are contained within each unit cell, the density(in g/ $cm^3$) of a totally crystalline PE will be? (Take the atomic weights for carbon and hydrogen as 12.01 g/mol and 1.008 g/mol, respectively and the avogadro's number as 6.023* $10^(23)$ repeat units/mol)

G-XEC-2017-11

NUM

53 to 53.2

Mechanical

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

G-XEC-2017-12

MATCH

A

Material Applications

Match the composites in column I with the most suitable application in Coloumn II: Coloumn I: [(P) Exfoliated silicates filled butyl rubber, (Q) Fiber reinforced aluminium alloy, (R)Silicon carbide whiskers reinforced alumina, (S) carbon particles reinforced plastic composites] Coloumn II: [(1) Automobile pistons, (2) Contact lenses, (3) Ski boards, (4) Tennis balls, (5) Cutting tool inserts for machining] Options: (A) P-4; Q-1; R-5; S-3 (B) P-2; Q-3; R-4; S-5 (C) P-3; Q-5; R-5; S-3 (D) P-2; Q-1; R-3; S-5

G-XEC-2017-13

MATCH

A

Material processing

Match the processes in Coloumn type I with products in Coloumn II: Coloumn I: [(P) Slip casting, (Q) Zone refining, (R)Sputtering, (S) Atomization] Coloumn II: [(1) Metal powders, (2) Thin films, (3) Ceramic parts, (4) Single crystal, (5) Metal sheets] Options: (A) P-3; Q-4; R-2; S-1 (B) P-2; Q-1; R-2; S-1 (C) P-3; Q-4; R-5; S-1 (D) P-3; Q-4; R-1; S-5

G-XEC-2017-16

MCQS

B

Miscellaneous

Which of the following statement(s) is/are true: (i) All piezoelectric materials are necessarily ferroelectric (ii) All ferroelectric materials are necessarily piezoelectric (iii) All pyroelectric materials are necessarily piezoelectric (iv) All pyroelectric materials are necessarily ferroelectric (A) (i) and (ii) (B) (ii) and (iii) (C) (i) and (iv) (D) (ii) and (iv)