36 Questions
What is the phenomenon where some polar crystals produce a small electric current when heated?
Pyroelectricity
Which of the following materials is an example of ferroelectric crystals?
KH2PO4
What is the name of the electricity produced by piezoelectric crystals when subjected to pressure?
Piezoelectricity
What is the property of crystals that act as mechanical-electric transducers?
Piezoelectric
Which of the following materials is an example of antiferroelectric crystals?
PbZrO3
What is the application of ferroelectric crystals in electronic devices?
Production of small sized capacitors of high capacitance
What is the characteristic of the electrical conductivity of semiconductors?
It increases with increase in temperature
What is the result of doping silicon with P (or As, group 5th elements)?
n-type semiconductor
What is the range of electrical conductivity of transition metal compounds like NiO, FeO, FeS?
10^(-4) - 10^(-6) ohm^(-1) cm^(-1)
What is the result of doping silicon with Ga (or In/Al, group 3rd elements)?
p-type semiconductor
What is the characteristic of the electrical conductivity of insulators?
It does not allow current to pass through
What is the term for the process of increasing the electrical conductivity of semiconductors by adding impurities?
Doping
What is the characteristic of permanent magnetism?
Magnetism is produced even in the absence of a magnetic field
Which of the following substances exhibits ferrimagnetism?
Fe3O4
What is the result of applying an electric field to a dielectric substance?
Polarization takes place due to the alignment of dipoles
What is the characteristic of antiferromagnetism?
Dipoles are aligned in opposite directions
Which of the following crystals exhibit piezoelectricity?
Certain crystals with net dipole moment
What is the cause of polarization in dielectric substances?
Nuclei are attracted to one side and the electron cloud to the other side
What is the reason for anions not occupying an interstitial site in a crystal?
Anions are larger in size compared to host atoms.
What type of defect arises when a foreign atom occupies a lattice site in place of a host atom?
Substitutional defect
What is the consequence of metal deficiency defects in a crystal?
Decrease in electrical conductivity
What is the result of the movement of an electron from an A+ ion in a crystal?
Creation of a positive hole
What type of semiconductor is formed when an electron is removed from an atom, resulting in a positive hole?
p-type semiconductor
What is the condition required for the formation of substitutional solid solutions?
The impurity should have a similar electronic structure to the host atom
What is the primary reason for the maintenance of electrical neutrality in metal excess defects due to interstitial cations?
Presence of an electron in the interstitial site
Which of the following compounds is likely to exhibit Frenkel defects due to the size difference between cations and anions?
AgCl
What is the characteristic of non-stoichiometric defects in crystals like ZnO?
Presence of trapped electrons in the neighborhood
Which of the following defects is not found in pure alkali metal halides?
Frenkel defect
What is the result of simultaneous occurrence of Schottky and Frenkel defects in a crystal?
Increase in electrical conductivity
Which of the following defects is responsible for the yellow color of non-stoichiometric ZnO?
Metal excess defect
What is the temperature at which a material enters the superconducting state?
Transition temperature
What is the characteristic of materials that exhibit superconductivity?
They offer no resistance to the flow of current
Which of the following materials is an example of a superconducting material?
Nb 3 Ge alloy
What is the phenomenon observed in lead (Pb) at 7.2 K?
Superconductivity
What is the behavior of diamagnetic substances when placed in a magnetic field?
They are feeblely repelled
Which of the following materials is an example of a paramagnetic substance?
Oxygen
Test your knowledge of piezoelectric crystals, their properties, and applications. Learn about Quartz, Rochelle's salt, and other piezoelectric materials used in devices like record players and audio tapes.
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