IIT JAM 2026: Geology
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JAM 2026 Confidential Geology (GG)
Section A: Q.1 – Q.10 Carry ONE mark each.
Q.1 Which one of the following primary structures can be used for paleocurrent
measurement?
(A) Oscillation ripple
(B) Hummocky cross-strata
(C) Flute cast
(D) Load and flame structures
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JAM 2026 Confidential Geology (GG)
Q.2 Which one of the following minerals does NOT show changes in optical
properties upon exposure to UV light?
(A) Apatite
(B) Calcite
(C) Fluorite
(D) Scheelite
Q.3 Choose the material on which 14C dating technique can be correctly applied.
(A) Charred food grains from the Indus Valley civilization
(B) Organic matter in carbonaceous chondrites
(C) Diamonds from the Earth’s interior
(D) Graphite from Proterozoic sedimentary basins
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JAM 2026 Confidential Geology (GG)
Q.4 Which one of the following rock combinations is characteristic of volcanic arcs?
(A) Basalt-andesite-dacite
(B) Basalt-trachyte-rhyolite
(C) Andesite-syenite-dacite
(D) Trachybasalt-basaltic andesite-andesite
Q.5 The rake (pitch) of slickenlines exposed on a moderately dipping fault plane
is the angle between
(A) the magnetic north and strike of the fault plane measured on a horizontal surface
(B) the strike of the fault plane and the slickenlines measured on the fault plane
(C) the strike of the fault plane and the slickenlines measured on a vertical plane
(D) the trend and the plunge directions of slickenlines measured on the fault plane
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JAM 2026 Confidential Geology (GG)
Q.6 Match the geographic locations listed in Column 1 to the geodynamic features
listed in Column 2.
Column 1 Column 2
P. Iceland i. Triple junction
Q. Afar ii. Plume-ridge interaction
R. Hawaii iii. Subduction zone
S. Aleutian Islands iv. Plume
(A) P-i; Q-ii; R-iv; S-iii
(B) P-ii; Q-i; R-iv; S-iii
(C) P-ii; Q-i; R-iii; S-iv
(D) P-ii; Q-iv; R-i; S-iii
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JAM 2026 Confidential Geology (GG)
Q.7 Which one of the following observations is consistent with the solid nature of the
Earth’s mantle?
(A) S waves propagate through the mantle
(B) S waves do not propagate through the mantle
(C) P waves opag
propagate through the mantle
(D) P waves are refracted in the mantle
Q.8 Which one of the following is a nektic bivalve?
(A) Gryphaea
(B) Trigonia
(C) Mytilus
(D) Solen
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JAM 2026 Confidential Geology (GG)
Q.9 Which one of the following is characteristic of a point bar succession?
(A) Thick homogenous sandstone
(B) Upward gradation from sandstone to shale
(C) Upward gradation from shale to sandstone
(D) Thick laminated shale
Q.10 Tsunamis are frequently caused by earthquakes at
(A) slow-spreading ridges
(B) fast-spreading ridges
(C) subduction zones
(D) transform faults
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JAM 2026 Confidential Geology (GG)
Section A: Q.11 – Q.30 Carry TWO marks each.
Q.11 In the 87Rb -87Sr isotopic systematics applied to terrestrial rocks, the slope of
the isochron ! "# $ 1% can be approximated as lt, where l is the decay constant
and t is time. Choose the correct option that justifies this approximation.
87
(A) Rb decays to 87Sr following a linear law
(B) The Rb/Sr ratio is susceptible to alteration in terrestrial rocks
(C) l is very small for 87Rb
(D) Age of the Earth > half-life of 87Rb
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JAM 2026 Confidential Geology (GG)
Q.12 A halide with octahedral cleavage can scratch calcite and can be scratched by
quartz. Identify the halide.
(A) Sylvite
(B) Fluorite
(C) Apatite
(D) Halite
Q.13 Choose the correct statement about Moho.
(A) Seismic and petrologic Moho coincide
(B) Seismic Moho lies at shallower depths relative to the petrologic Moho
(C) Petrologic Moho lies at shallower depths relative to the seismic Moho
(D) Petrologic Moho lies above the layered gabbro in ophiolites
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JAM 2026 Confidential Geology (GG)
Q.14 Stratigraphic sections S1 and S2, separated by tens of kilometers, are shown in
the schematic. The line segments in this schematic represent biostratigraphic
correlation between S1 and S2. Which one of the segments (P, Q, R, S) of this
correlation line represents an unconformity?
(A) P
(B) Q
(C) R
(D) S
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JAM 2026 Confidential Geology (GG)
Q.15 The S wave velocity &' is given by &' = ()+*, where ) is shear modulus and *
is density of the medium. &' is lower in mantle plumes than in the ambient mantle
because of
(A) lower temperature of mantle plumes
(B) lower density of mantle plumes
(C) higher density of mantle plumes
(D) lower shear modulus of mantle plumes
Q.16
Which one of the following environments best characterizes the natural habitat
of boring valv
bivalves, green algae, and herbivorous snails?
(A) Deep marine
(B) Rocky intertidal coast
(C) Outer shelf
(D) Estuary
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JAM 2026 Confidential Geology (GG)
Q.17 Match the minerals in Column 1 to their characteristic optical properties in
Column 2.
Column 1 Column 2
P. Zircon i. Pink to green pleochroism
Q. Orthopyroxene ii. Very high positive relief
R. Muscovite iii. Cyclic twinning
S. Cordierite iv. Third order birefringence
(A) P-ii; Q-i; R-iii; S-iv
(B) P-i; Q-ii; R-iv; S-iii
(C) P-ii; Q-i; R-iv; S-iii
(D) P-ii; Q-iv; R-i; S-iii
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JAM 2026 Confidential Geology (GG)
Q.18 Match the magma series in Column 1 to the geological settings in Column 2.
Column 1 Column 2
P. Alkaline Series i. Divergent oceanic margin
Q. Shoshonite Series ii. Oceanic intraplate
R. Calc-alkaline Series iii. Convergent plate margin
iv. Convergent plate margin
S. Tholeiitic Series
close to back arc
(A) P-i; Q-iv; R-iii; S-ii
(B) P-ii; Q-iv; R-iii; S-i
(C) P-ii; Q-i; R-iii; S-iv
(D) P-iv; R-ii; Q-i; S-iii
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JAM 2026 Confidential Geology (GG)
Q.19 Match the plant fossils in Column 1 to the corresponding geological ages in
Column 2.
Column 1 Column 2
P. Glossopteris i. Triassic
Q. Ptilophyllum ii. Devonian
R. Dicrodium-Thinnfeldic iii. Triassic to Lower
Cretaceous
S. Psilophyton iv. Permian
(A) P-iv; Q-iii; R-i; S-ii
(B) P-iii; Q-iv; R-i; S-ii
(C) P-iv; Q-iii; R-ii; S-i
(D) P-iv; Q-i; R-iii; S-ii
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JAM 2026 Confidential Geology (GG)
Q.20 Which one of the following reasons best explains the occurrence of large number
of earthquakes at the active plate boundaries compared to the plate interiors?
(A) Strain energy accumulation is higher at the plate boundaries
(B) Stiffness is higher at the plate boundaries
(C) Heat flow is lower at the plate boundaries
(D) Crust is thinner at the plate boundaries
Q.21
If P, Q, R, and S refer to Rainfall induced landslide, Bolide impact, Milankovitch
cycle, and Supercontinent cycle, respectively, then which one of the following
correctly pres
represents the decreasing order of their duration?
(A) S, R, P, Q
(B) Q, P, R, S
(C) S, Q, P, R
(D) S, P, Q, R
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JAM 2026 Confidential Geology (GG)
Q.22
The schematic shows a geological cross-section of a faulted region of
sedimentary rocks (beds P to U). Assuming continuous sedimentation, select
the beds that record the earliest activation and the latest reactivation of the fault.
(A) Q, T
(B) P, T
(C) Q, R
(D) Q, U
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JAM 2026 Confidential Geology (GG)
Q.23 In a single layer of an anticline, the dip isogons converge towards the inner
surface (core). Which one of the following statements is correct for the
curvature of the inner surface of this folded layer?
(A) Curvature of the inner surface > Curvature of the outer surface
(B) Curvature of the inner surface < Curvature of the outer surface
(C) Curvature of the inner surface = Curvature of the outer surface
(D) Curvature of the inner surface = Curvature of the median surface
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JAM 2026 Confidential Geology (GG)
Q.24
In an arid environment, winds of similar intensity blow in nearly opposite
directions in alternate seasons. Which dune type is most likely to form in
such an environment?
(A) Barkhan
(B) Transverse dunes
(C) Seif
(D) Lunate
Q.25 Which one of the following features is used to define the K-Pg boundary
globally?
(A) Absence of dinosaur fossils
(B) Presence of iridium anomaly in sediments
(C) Presence of high mercury content in sediments
(D) End of Deccan volcanism
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JAM 2026 Confidential Geology (GG)
Q.26 The figure shows chemogenic mineral projections for Facies P and Facies Q.
Which one of the following reactions best represents change from Facies P to
Facies Q?
(A) Wo + An = Sil + Qtz
(B) An + Sil = Wo
(C) Wo + Crn = Grs
(D) Grs + Qtz = Wo + An
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JAM 2026 Confidential Geology (GG)
Q.27 The figure depicts stability fields of minerals P and Q. Which one of the following
statements is INCORRECT?
(A) P and Q can coexist at different temperatures only if pressures are different
(B) P and Q can coexist with liquid only at one pressure and temperature
(C) Q has a higher melting temperature at higher pressures than at lower pressures
(D) A reaction forming Q from P at constant pressure will require an input of heat
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JAM 2026 Confidential Geology (GG)
Q.28 Match the metal associations in Column 1 to corresponding hosts in Column 2.
Column 1 Column 2
P. Cu, Co, Zn i. Tectonized dunite and harzburgite
Q. Mn, Co, Ni ii. MORB
R. Cr iii. I-Type granite in volcanic arc
S. Cu, Mo, Pb iv. Pelagic sediment
(A) P-ii; Q-iv; R-i; S-iii
(B) P-iv; Q-ii; R-i; S-iii
(C) P-ii; Q-iv; R-iii; S-i
(D) P-ii; Q-i; -i
R-iv; S-iii
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JAM 2026 Confidential Geology (GG)
Q.29
Which one of the following mineral associations is diagnostic of the highly-
oxidized zone of a weathered primary base metal vein?
(A) Smithsonite, Malachite, Anglesite
(B) Calcite, Fluorite, Pyrite
(C) Limonite, Realgar, Chalcocite
(D) Goethite, Orpiment, Boehmite
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JAM 2026 Confidential Geology (GG)
Q.30 Match the features in Column 1 to the most appropriate description in Column 2.
Column 1 Column 2
P. Ash layer i. Part of a turbidite sequence
Q. Graded bedding ii. Subaerial episode in the sedimentary record
R. Hiatus iii. Dating of sedimentary rocks
S. Soil profile iv. Missing faunal zone
(A) P-iii; Q-i; R-iv; S-ii
(B) P-i; Q-iii; R-iv; S-ii
(C) P-iii; Q-i; R-ii; S-iv
(D) P-iii; Q-iv; R-i; S-ii
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JAM 2026 Confidential Geology (GG)
Section B: Q.31 – Q.40 Carry TWO marks each.
Q.31 Choose the correct statement(s) related to different aspects of volcanism.
(A) Andesites are the most common rock type associated with stratovolcanoes
(B) Explosiveness of volcanism depends on viscosity and fluid content of the magma
(C) Shield volcanoes represent one of the largest magmatic vent landforms
(D) Pillow lavas reflect sub-aerial volcanic eruptions
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JAM 2026 Confidential Geology (GG)
Q.32 Which of the following processes is/are responsible for the alternate bands of
magnetic polarity observed in seafloor basalts?
(A) Convection in the mantle
(B) Convection in the outer core
(C) Convection in the inner core
(D) Seismicity at mid-oceanic ridges
Q.33 The Earth’s gravitational acceleration is higher at the poles compared to that at the
equator due to
(A) higher density rocks at the poles
(B) shorter polar radius
(C) lower centrifugal acceleration at the poles
(D) higher topography at the poles
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JAM 2026 Confidential Geology (GG)
Q.34 During glacier retreat following the last Ice Age, Scandinavia experienced
isostatic rebound. Which of the following resulted due to this rebound?
(A) Fall in water level in glacial lakes
(B) Rise in water level in glacial lakes
(C) Raised beaches
(D) Deep earthquakes
Q.35 Natural cumu
accumulation of hydrocarbons are expected to occur
(A) in an anticline
(B) in stratigraphic traps
(C) along synclinal axial troughs
(D) in ancient delta-mouth bars
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JAM 2026 Confidential Geology (GG)
Q.36 Which of the following factors affect(s) the intrinsic spatial resolution of remote
sensing imagery?
(A) Sensor pixel size
(B) Altitude of the satellite
(C) Wavelength of the captured electromagnetic radiation
(D) Satellite mmun
communication bandwidth
Q.37 Two sandstone reservoir rocks R1 and R2 have 25% porosity each but the
permeability of R1 is higher than that of R2. Which of the following can explain
this difference in permeability?
(A) Clay content in R1 is more than that in R2
(B) Microfracture density in R1 is higher than that in R2
(C) Sorting in R1 is better than that in R2
(D) R1 has more angular grains than R2
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JAM 2026 Confidential Geology (GG)
Q.38 In the following illustration, PQRS is an exposed axial planar cleavage,
striking north-south and dipping 40° east. B1 and B2 are the traces of two
folded bedding planes on this axial planar cleavage. The fold can be classified as
(A) horizontal fold
(B) inclined fold
(C) plunging fold
(D) upright fold
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JAM 2026 Confidential Geology (GG)
Q.39 Intrusion of a 10-meter thick dolerite dyke into a boron-rich quartz-garnet-biotite-
muscovite-chlorite schist developed a visible symmetric baked zone. Which of the
following minerals can develop in this baked zone, 2 meters away from the margin
of the dyke?
(A) Orthopyroxene
(B) Clinopyroxene
(C) Amphibole
(D) Tourmaline
Q.40 Which of the following ore types form(s) by magmatic differentiation?
(A) Gold in quartz vein
(B) Titaniferous magnetite in anorthosite
(C) Columbite-Tantalite in pegmatite
(D) Chromite-Pentlandite in pyroxenite
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JAM 2026 Confidential Geology (GG)
Section C: Q.41 – Q.50 Carry ONE mark each.
Q.41 One mole of a parent nuclide is undergoing radioactive decay. The fraction of
atoms of this nuclide that has decayed after three half-lives is ____________.
(Round off to three decimal places)
Q.42 The lithostatic pressure at the base of a 35 km thick continental crust of average
____________ × 108 Pa. (Round off to one decimal place)
density of 2.8 g/cc is _____
(Consider the value of acceleration due to gravity as 9.8 m/s2)
Q.43 A hypothetical mineral has the formula X7Si8O22(OH)2, where X is a cation.
The valence state of X is _________. (In integer)
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JAM 2026 Confidential Geology (GG)
Q.44 The surface subsidence at a horizontal distance , from the centerline of a
34 5
cylindrical tunnel is given by -./0 × exp 2 :;<where -./0 is the
6789 5
maximum subsidence above the tunnel and > = ?@ m is the depth of the tunnel
centerline. The ratio of surface subsidence at , = 1@ m to that at , = A@ m
is __________. (Round off to one decimal place)
Q.45 An aquifer with a hydraulic conductivity of 60 m/day experiences a head loss
of 20 m over a length of 1000 m. The flow of water per unit area, in millimeter
per minute, is ____________ . (Round off to two decimal places)
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JAM 2026 Confidential Geology (GG)
Q.46 Sphalerite shows limited isomorphism. Consider a colourless sphalerite having
33% S and 67% Zn. Then, in a black-coloured sphalerite, with a 15% Fe
substitution, the ratio of atomic proportions of Zn to that of Fe is ____________
(Round off to one decimal place)
(Given: atomic weight of Zn = 65.37, Fe = 55.85, and S = 32.06)
Q.47 The true dip of a normal limb associated with asymmetric folding is 20° and the
angle that this limb makes with the axial planar cleavage is 35°. The true dip of
the axial planar cleavage, in degree, is ______________ . (In integer)
Q.48 A metallic mineral weighs 44 g and displaces 11 mL of water when fully
immersed. The density of the mineral is ____________ g/cc. (In integer)
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JAM 2026 Confidential Geology (GG)
Q.49 A clinopyroxene crystal in a basalt, measured to have a composition of
Mg1.2Fe0.4Ca0.4Si2O6, will have Mg-number (Mg#) of ____________ %.
(In integer)
Q.50 The figure shows a coral reef deposit at the continental margin since 120 Ma.
Assuming that there was no sea-level change, the average subsidence rate of
this continental margin is ______________ mm/year. (Round off to three decimal
places)
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JAM 2026 Confidential Geology (GG)
Section C: Q.51 – Q.60 Carry TWO marks each.
Q.51 eNd is the deviation of 143Nd/144Nd of a sample relative to CHUR in
parts per 104. For a pyroxenite with measured 143Nd/144Nd = 0.512838 and
147
Sm/144Nd = 0.21, the initial eNd at 1 Ga is ______________ . (Round off only
the final answer to one decimal place)
(Given: for CHUR, 143Nd/144Nd = 0.512638 and 147Sm/144Nd = 0.1967. The decay
constant for 147Sm is 6.54 ×10−12 yr−1)
Q.52 A sandstone sample with 100% quartz has a porosity of 30%. The sample is dry
and the density of quartz is 2.65 g/cc. The bulk density of the sandstone sample
is _________ g/cc (Round off to one decimal place)
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JAM 2026 Confidential Geology (GG)
Q.53
A mountain of height 5 km is in static equilibrium with a crustal block of zero
elevation. If the density of the crust and the mantle are 2700 and 3300 kg/m3,
respectively, the thickness of the mountain root (h) is ________ km (Round off
to one decimal place)
Q.54 In a mineralized staurolite-garnet-biotite schist, the estimated metasomatic sulfide
mineralization is 4%, with ore mineral proportions as 30% chalcopyrite, 20%
pyrite and the rest being magnetite. The maximum grade of Cu will be
__________ /t
g/ton (Round off to the nearest integer)
(Given: 1 ton = 1000 kg; atomic weight of Cu = 63.55, Fe = 55.85, O = 16.00
and S = 32.06)
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JAM 2026 Confidential Geology (GG)
Q.55
Four vertical boreholes are drilled on a flat topography at 50 m intervals along
the east-west direction. The boreholes intersect a coal seam at depths of 100 m,
130 m, 160 m and 190 m. The true dip of the coal seam, in degree, is _______.
(Round off to two decimal places)
Q.56 Consider a perfect Geocentric Axial Dipole model for the geomagnetic field. At a
latitude of 30°N, the inclination of a freely suspended magnetic needle, in degree,
is __________ . (Round off to the nearest integer)
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JAM 2026 Confidential Geology (GG)
Q.57
The figure shows the 14C activity with depth in a sediment core from a lake,
where the sedimentation rate was uniform. The maximum 14C activity, marking
the signature of bomb carbon, was measured at a depth of 45 cm. The rate of
sedimentation is __________ mm/year (In integer)
(Given: the core top reflects the year of coring and bomb carbon reached its
global maximum in 1965)
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JAM 2026 Confidential Geology (GG)
Q.58 Based on the figure, the anorthite content of first formed plagioclase crystals from
a liquid composition having 50 mole % anorthite is _________ mole % (In integer)
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JAM 2026 Confidential Geology (GG)
Q.59 The figure shows variation in optical properties of plagioclase feldspars
with composition. A feldspar from a lunar anorthosite, with anorthite mole%
of 85, will have a birefringence of ____________ (Round off to three decimal
places)
Q.60
In the isometric system, the difference in the number of symmetry planes in class
CBDE (Hextetrahedral) class and F DC (Diploidal) is ____________ (In integer)
.
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JAM 2026: Geology (GG)
Master Answer Key
Question
Subject Question Type Answer Key/Range Mark(s)
No.
1 GG MCQ C 1
2 GG MCQ A 1
3 GG MCQ A 1
4 GG MCQ A 1
5 GG MCQ B 1
6 GG MCQ B 1
7 GG MCQ A 1
8 GG MCQ MTA 1
9 GG MCQ B 1
10 GG MCQ C 1
11 GG MCQ C 2
12 GG MCQ B 2
13 GG MCQ B 2
14 GG MCQ B 2
15 GG MCQ D 2
16 GG MCQ B 2
17 GG MCQ C 2
18 GG MCQ B 2
19 GG MCQ A 2
20 GG MCQ A 2
21 GG MCQ A 2
22 GG MCQ A 2
23 GG MCQ A 2
24 GG MCQ C 2
25 GG MCQ B 2
26 GG MCQ D 2
27 GG MCQ D 2
28 GG MCQ A 2
29 GG MCQ A 2
30 GG MCQ A 2
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Question
Subject Question Type Answer Key/Range Mark(s)
No.
31 GG MSQ A;B;C 2
32 GG MSQ A;B 2
33 GG MSQ B;C 2
34 GG MSQ A;C 2
35 GG MSQ A;B;D 2
36 GG MSQ A;B;C 2
37 GG MSQ B;C 2
38 GG MSQ B;C 2
39 GG MSQ C;D 2
40 GG MSQ B;D 2
41 GG NAT 0.875 to 0.875 1
42 GG NAT 9.5 to 9.7 1
43 GG NAT 2 to 2 1
44 GG NAT 1.2 to 1.4 1
45 GG NAT 0.80 to 0.85 1
46 GG NAT 2.9 to 3.1 1
47 GG NAT 55 to 55 1
48 GG NAT 4 to 4 1
49 GG NAT 75 to 75 1
50 GG NAT 0.025 to 0.025 1
51 GG NAT 2.1 to 2.3 2
52 GG NAT 1.8 to 2.0 2
53 GG NAT 22.4 to 22.6 2
54 GG NAT 4100 to 4200 2
55 GG NAT 30.00 to 32.00 2
56 GG NAT 48 to 50 2
57 GG NAT 10 to 10 2
58 GG NAT 85 to 90 2
59 GG NAT 0.010 to 0.015 2
60 GG NAT 3 to 3 2Page 1 of 38
Source: Indian Institutes of Technology. Question paper published by Indian Institutes of Technology.