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question_answer1)
Certain crystals produce electric signals on application of pressure. This phenomenon is called [BHU 2005]
A)
Pyroelectricity done
clear
B)
Ferroelectricity done
clear
C)
Peizoelectricity done
clear
D)
Ferrielectricity done
clear
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question_answer2)
Which defect causes decrease in the density of crystal [KCET 2000, 05]
A)
Frenkel done
clear
B)
Schottky done
clear
C)
Interstitial done
clear
D)
\[F-\]centre done
clear
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question_answer3)
The correct statement regarding \[F-\]centre is
A)
Electron are held in the voids of crystals done
clear
B)
\[F-\]centre produces colour to the crystals done
clear
C)
Conductivity of the crystal increases due to \[F-\]centre done
clear
D)
All done
clear
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question_answer4)
Doping of silicon (Si) with boron B leads to [UPSEAT 2004]
A)
\[n\]-type semiconductor done
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B)
\[p\]-type semiconductor done
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C)
Metal done
clear
D)
Insulator done
clear
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question_answer5)
If \[NaCl\] is doped with \[{{10}^{-3}}mol\ %\,\,SrC{{l}_{2}},\] then the concentration of cation vacancies will be
A)
\[1\times {{10}^{-3}}mol%\] done
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B)
\[2\times {{10}^{-3}}mol%\] done
clear
C)
\[3\times {{10}^{-3}}mol%\] done
clear
D)
\[4\times {{10}^{-3}}mol%\] done
clear
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question_answer6)
In the laboratory, sodium chloride is made by burning the sodium in the atmosphere of chlorine which is yellow in colour. The cause of yellow colour is
A)
Presence of \[N{{a}^{+}}\]ions in the crystal lattice done
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B)
Presence of \[C{{l}^{-}}\]ions in the crystal lattice done
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C)
Presence of electron in the crystal lattice done
clear
D)
Presence of face centered cubic crystal lattice done
clear
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question_answer7)
Frenkel defect is caused due to [MP PET 1994]
A)
An ion missing from the normal lattice site creating a vacancy done
clear
B)
An extra positive ion occupying an interstitial position in the lattice done
clear
C)
An extra negative ion occupying an interstitial position in the lattice done
clear
D)
The shift of a positive ion from its normal lattice site to an interstitial site done
clear
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question_answer8)
Which one of the following has Frenkel defect [MP PMT 2000]
A)
Sodium chloride done
clear
B)
Graphite done
clear
C)
Silver bromide done
clear
D)
Diamond done
clear
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question_answer9)
Schottky defect generally appears in [DCE 2004]
A)
\[NaCl\] done
clear
B)
\[KCl\] done
clear
C)
\[CsCl\] done
clear
D)
All of these done
clear
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question_answer10)
Schottky defect in crystals is observed when [CBSE PMT 1998; KCET 2002]
A)
Density of crystal is increased done
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B)
Unequal number of cations and anions are missing from the lattice done
clear
C)
An ion leaves its normal site and occupies an interstitial site done
clear
D)
Equal number of cations and anions are missing from the lattice done
clear
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question_answer11)
Ionic solids, with Schottky defects, contain in their structure [CBSE PMT 1994]
A)
Equal number of cation and anion vacancies done
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B)
Anion vacancies and interstitial anions done
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C)
Cation vacancies only done
clear
D)
Cation vacancies and interstitial cations done
clear
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question_answer12)
The following is not a function of an impurity present in a crystal [MP PET 1995]
A)
Establishing thermal equilibrium done
clear
B)
Having tendency to diffuse done
clear
C)
Contributing to scattering done
clear
D)
Introducing new electronic energy levels done
clear
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question_answer13)
Due to Frenkel defect, the density of ionic solids [MP PET 1996; MP PMT 2002]
A)
Increases done
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B)
Decreases done
clear
C)
Does not change done
clear
D)
Changes done
clear
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question_answer14)
Point defects are present in [MP PMT 1997]
A)
Ionic solids done
clear
B)
Molecular solids done
clear
C)
Amorphous solids done
clear
D)
Liquids done
clear
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question_answer15)
If a non-metal is added to the interstitial sites of a metal then the metal becomes [DCE 2001]
A)
Softer done
clear
B)
Less tensile done
clear
C)
Less malleable done
clear
D)
More ductile done
clear
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question_answer16)
In \[AgBr\] crystal, the ion size lies in the order \[A{{g}^{+}}<<B{{r}^{-}}.\] The \[AgBr\] crystal should have the following characteristics
A)
Defectless (perfect) crystal done
clear
B)
Schottky defect only done
clear
C)
Frenkel defect only done
clear
D)
Both Schottky and Frenkel defects done
clear
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question_answer17)
Frenkel and Schottky defects are [BHU 2003]
A)
Nucleus defects done
clear
B)
Non-crystal defects done
clear
C)
Crystal defects done
clear
D)
None of these done
clear
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question_answer18)
Which one of the following is the most correct statement
A)
Brass is an interstitial alloy, while steel is a substitutional alloy done
clear
B)
Brass is a substitutional alloy, while steel is an interstitial alloy done
clear
C)
Brass and steel are both substitutional alloys done
clear
D)
Brass and steel are both interstitial alloys done
clear
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question_answer19)
The flame colours of metal ions are due to [KCET 2003]
A)
Frenkel defect done
clear
B)
Schottky defect done
clear
C)
Metal deficiency defect done
clear
D)
Metal excess defect done
clear
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question_answer20)
Which one of the following crystals does not exhibit Frenkel defect [MP PET 2002]
A)
AgBr done
clear
B)
AgCl done
clear
C)
KBr done
clear
D)
ZnS done
clear
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question_answer21)
In a solid lattice the cation has left a lattice site and is located at an interstitial position, the lattice defect is [AIIMS 1982, 1991; DCE 2002; J & K 2005]
A)
Interstitial defect done
clear
B)
Valency defect done
clear
C)
Frenkel defect done
clear
D)
Schottky defect done
clear
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question_answer22)
When electrons are trapped into the crystal in anion vacancy, the defect is known as [BHU 2005]
A)
Schotky defect done
clear
B)
Frenkel defect done
clear
C)
Stoichiometric defect done
clear
D)
F-centres done
clear
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question_answer23)
Schottky defect defines imperfection in the lattice structure of a [AIIMS 2002]
A)
Solid done
clear
B)
Liquid done
clear
C)
Gas done
clear
D)
Plasma done
clear
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