Geology and Geophysics
GATE GG-1 Crystallography and mineralogy PYQs
Build your understanding with focused practice from past exam papers.
Questions 31–38 of 38. Imported answers require independent review unless marked reviewed.
Question 20
Open questionGL-1NAT2 marksNeeds review
The unit-cell of an orthorhombic mineral was compressed during deformation from 5 Å to 4.5 Å along the c-axis, with the other two dimensions remaining unaffected. The absolute value of the shift in the position of the (001) peak in its XRD pattern is ________ °2θ. (Round off to 3 decimal places) (Wavelength of X-ray used = 1.5418 Å. For orthorhombic system:
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 31
Open questionPART-B SECTION-1MCQ2 marksNeeds review
Match the type of twining (Group I) with the mineral (Group II) that best exhibits it.
Group I
P. Carlsbad
Q. Pericline
R. Brazil
S. Geniculated (elbow)
Group II
Rutile
Quartz
Orthoclase
Plagioclase
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Open questionPART-B SECTION-1MCQ2 marksNeeds review
On inserting a first order red interference filter in SE-NW direction, the interference figure of quartz shows
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Open questionPART-B GEOLOGY (SECTION 1)MCQ2 marksNeeds review
Match the optical properties listed in Group I with the corresponding mineral in Group II.
Group I
P. Brown colour, very high refractive index, very high birefringence, biaxial positive
Q. Colourless, very high refractive index, low birefringence, uniaxial negative
R. Deep reddish-brown colour, very high refractive index, very high birefringence, uniaxial positive
S. Colourless, very high refractive index, very high birefringence, uniaxial positive
Group II
Apatite
Rutile
Zircon
Titanite
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Open questionPART-B GEOLOGY (SECTION 1)NAT2 marksNeeds review
The difference in the number of faces in forms and in the holosymmetric class of the isometric system is ____________.
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 12
Open questionGG-CMCQ1 markNeeds review
The figure below shows the intercepts of the plane HKL with the crystallographic axes a, b, c. The Miller index of the plane HKL is
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 37
Open questionGG-1NAT2 marksNeeds review
Fluorite crystal (CaF₂) adopts face-centered cubic structure with lattice parameter a = 5.463 Å. If the ionic radius of anion (F⁻) is 1.71 Å, the ionic radius of cation (Ca²⁺) is __________ Å.
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Open questionGG-1MCQ2 marksNeeds review
The diagram below shows the interference figure of a mineral. The mineral is
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