Selenium is _____ semiconductor.
Selenium is _____ semiconductor.
In thermocouples which of the following pairs is commonly used ?
In thermocouples which of the following pairs is commonly used ?
Carbon resistors are used extensively because they are
Carbon resistors are used extensively because they are
The current due to electron flow in conduction band is the hole current in valence band.
The current due to electron flow in conduction band is the hole current in valence band.
Commonly used conducting materials are
Commonly used conducting materials are
The conductivity of an extrinsic semiconductor with temperature
The conductivity of an extrinsic semiconductor with temperature
Effect of moisture on the insulating materials is to
Effect of moisture on the insulating materials is to
Spark plug makes use of which of the following materials for insulation ?
Spark plug makes use of which of the following materials for insulation ?
__________ is the main constituent of glass
__________ is the main constituent of glass
The metal having the lowest temperature coefficient of resistance is
The metal having the lowest temperature coefficient of resistance is
The impurity atoms is semiconductors
The impurity atoms is semiconductors
Which of the following materials does not have covalent bonds ?
Which of the following materials does not have covalent bonds ?
Due to which of the following reasons aluminium does not corrode in atmosphere ?
Due to which of the following reasons aluminium does not corrode in atmosphere ?
The conductors have transport phenomena of electrons due to
The conductors have transport phenomena of electrons due to
________ has the best damping properties.
________ has the best damping properties.
The coils of D.C. motor starter are wound with wire of
The coils of D.C. motor starter are wound with wire of
Which of the following materials is used for making coils of standard resistances ?
Which of the following materials is used for making coils of standard resistances ?
A good electric contact material should have all of the following properties except
A good electric contact material should have all of the following properties except
The superconductivity is due to
The superconductivity is due to
Carbon bearings are used under which of the following conditions ?
Carbon bearings are used under which of the following conditions ?
Due to which of the following fact, in India, aluminium is replacing copper ?
Due to which of the following fact, in India, aluminium is replacing copper ?
Which of the following variety of copper has the best conductivity ?
Which of the following variety of copper has the best conductivity ?
Platinum is used in
Platinum is used in
Addition of 0.3 to 4.5% silicon to iron __________ the electrical resistivity of iron.
Addition of 0.3 to 4.5% silicon to iron __________ the electrical resistivity of iron.
Is viscoelastic.
Is viscoelastic.
Which of the following materials is the best conductor of electricity ?
Which of the following materials is the best conductor of electricity ?
Is a negatively charged particle present in an atom.
Is a negatively charged particle present in an atom.
A highly conductive material must have
A highly conductive material must have
Most of the common metals have _________ structure.
Most of the common metals have _________ structure.
High resistivity materials are used in
High resistivity materials are used in
Is the property of absorbing moisture from atmosphere.
Is the property of absorbing moisture from atmosphere.
The transition temperature of mercury is
The transition temperature of mercury is
A perfect conductor has
A perfect conductor has
Super conductivity can be destroyed by
Super conductivity can be destroyed by
Which of the following materials is preferred for transmitting electrical energy over long distance ?
Which of the following materials is preferred for transmitting electrical energy over long distance ?
The minority carrier concentration is largely a function of
The minority carrier concentration is largely a function of
In graphite, bonding is
In graphite, bonding is
Thermonic emission occurs in
Thermonic emission occurs in
Superconducting metal in super conducting state has relative permeability of
Superconducting metal in super conducting state has relative permeability of
_______ is an example of piezoelectric material.
_______ is an example of piezoelectric material.
Carbon electrodes are not used in
Carbon electrodes are not used in
For a particular material the Hall coefficient was found to be zero. The material is
For a particular material the Hall coefficient was found to be zero. The material is
The kinetic energy of a bounded electron is
The kinetic energy of a bounded electron is
The formula __________ determines the number of electrons that can be accommodated in any level.
The formula __________ determines the number of electrons that can be accommodated in any level.
Which of the following affect greatly the resistivity of electrical conductors?
Which of the following affect greatly the resistivity of electrical conductors?
Overhead telephone wires are made of
Overhead telephone wires are made of
Non-linear resistors
Non-linear resistors
Which of the following factors affect resistivity of metals ?
Which of the following factors affect resistivity of metals ?
Superconductors are becoming popular for use in
Superconductors are becoming popular for use in
Low resistivity materials are used in
Low resistivity materials are used in
The forbidden gap in an insulator is
The forbidden gap in an insulator is
A carbon resistor contains
A carbon resistor contains
An H.R.C. fuse is
An H.R.C. fuse is
_________ is most commonly used for making magnetic recording tape
_________ is most commonly used for making magnetic recording tape
By increasing impurity content in the metal alloy the residual resistivity always
By increasing impurity content in the metal alloy the residual resistivity always
Carbon rods are used in wet and dry cells because
Carbon rods are used in wet and dry cells because
Which of the following is a semiconductor material ?
Which of the following is a semiconductor material ?
For a hole which of the following statements is incorrect ?
For a hole which of the following statements is incorrect ?
On which of the following factors does the resistivity of a material depend ?
On which of the following factors does the resistivity of a material depend ?
The conductivity of a conductor can be increased by
The conductivity of a conductor can be increased by
The covalent bond is formed by
The covalent bond is formed by
Mercury as an electric contact material is
Mercury as an electric contact material is
Solder is an alloy of
Solder is an alloy of
The number of atoms per unit cell in B.C.C. structure is
The number of atoms per unit cell in B.C.C. structure is
The converse of hardness is known as
The converse of hardness is known as
Copper, even though costly, finds use in the windings of electrical machines because
Copper, even though costly, finds use in the windings of electrical machines because
In conductors conduction of electricity takes place due to movement of
In conductors conduction of electricity takes place due to movement of
Is an element used in semiconductors whose atoms have three valence electrons.
Is an element used in semiconductors whose atoms have three valence electrons.
The structure sensitive property of a super conductor is
The structure sensitive property of a super conductor is
The carbon percentage is least in
The carbon percentage is least in
In a superconductor the value of critical density depends upon
In a superconductor the value of critical density depends upon
Which of the following are non-conductors of electricity?
Which of the following are non-conductors of electricity?
Which of the following is the poorest conductor of electricity ?
Which of the following is the poorest conductor of electricity ?
In a crystal, an atom vibrates at a frequency determined by
In a crystal, an atom vibrates at a frequency determined by
Surface resistance of an insulating material is reduced due to the
Surface resistance of an insulating material is reduced due to the
The resistivity of a metal is a function of temperature because
The resistivity of a metal is a function of temperature because
Which of the following resistive materials has the lowest temperature co-efficient of resistance ?
Which of the following resistive materials has the lowest temperature co-efficient of resistance ?
At transition temperature the value of critical field is
At transition temperature the value of critical field is
For germanium the forbidden energy gap is
For germanium the forbidden energy gap is
Which of the following material is not a semiconductor ?
Which of the following material is not a semiconductor ?
If the resistance of a conductor does not vary in accordance with Ohm’s law it is known as
If the resistance of a conductor does not vary in accordance with Ohm’s law it is known as
The photo-electric effect occurs only when the incident light has more than a certain critical
The photo-electric effect occurs only when the incident light has more than a certain critical
Due to which of the following reasons copper and aluminium are not used for heating elements ?
Due to which of the following reasons copper and aluminium are not used for heating elements ?
_______ is a hard solder.
_______ is a hard solder.
The tiny block formed by the arrangement of a small group of atoms is called the
The tiny block formed by the arrangement of a small group of atoms is called the
_______ has zero temperature co-efficient of resistance.
_______ has zero temperature co-efficient of resistance.
Thermocouples are mainly used for the measurement of
Thermocouples are mainly used for the measurement of
The value of critical field below the transition temperature will
The value of critical field below the transition temperature will
Piezoelectric materials serve as a source of ________ .
Piezoelectric materials serve as a source of ________ .
The conduction of electricity, in semiconductors, takes place due to movement of
The conduction of electricity, in semiconductors, takes place due to movement of
Which of the following is an advantage of stranded conductor over equivalent single conductor ?
Which of the following is an advantage of stranded conductor over equivalent single conductor ?
Constantan contains
Constantan contains
Total number of crystal systems is
Total number of crystal systems is
Substances whose specific resistance abruptly decreases at very low temperature are called
Substances whose specific resistance abruptly decreases at very low temperature are called
The conductivity of a metal is determined by
The conductivity of a metal is determined by
The co-ordination number of a simple cubic structure is
The co-ordination number of a simple cubic structure is
Due to which of the following factors the brush wear rate is altered?
Due to which of the following factors the brush wear rate is altered?
Steel wire is used as
Steel wire is used as
Which of the following high resistance materials has the highest operating temperature ?
Which of the following high resistance materials has the highest operating temperature ?
