In a crystal, an atom vibrates at a frequency determined by
In a crystal, an atom vibrates at a frequency determined by
Which of the following factors affect resistivity of metals ?
Which of the following factors affect resistivity of metals ?
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 ?
The conductivity of a conductor can be increased by
The conductivity of a conductor can be increased by
The superconductivity is due to
The superconductivity is due to
At transition temperature the value of critical field is
At transition temperature the value of critical field is
Effect of moisture on the insulating materials is to
Effect of moisture on the insulating materials is to
Super conductivity can be destroyed by
Super conductivity can be destroyed by
The minority carrier concentration is largely a function of
The minority carrier concentration is largely a function of
The metal having the lowest temperature coefficient of resistance is
The metal having the lowest temperature coefficient of resistance is
In a superconductor the value of critical density depends upon
In a superconductor the value of critical density depends upon
By increasing impurity content in the metal alloy the residual resistivity always
By increasing impurity content in the metal alloy the residual resistivity always
Thermocouples are mainly used for the measurement of
Thermocouples are mainly used for the measurement of
The conductors have transport phenomena of electrons due to
The conductors have transport phenomena of electrons due to
Carbon resistors are used extensively because they are
Carbon resistors are used extensively because they are
In graphite, bonding is
In graphite, bonding is
Which of the following high resistance materials has the highest operating temperature ?
Which of the following high resistance materials has the highest operating temperature ?
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 ?
Constantan contains
Constantan contains
Is a negatively charged particle present in an atom.
Is a negatively charged particle present in an atom.
Which of the following is the poorest conductor of electricity ?
Which of the following is the poorest conductor of electricity ?
Which of the following materials does not have covalent bonds ?
Which of the following materials does not have covalent bonds ?
Non-linear resistors
Non-linear resistors
Thermonic emission occurs in
Thermonic emission occurs in
Total number of crystal systems is
Total number of crystal systems is
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 ?
High resistivity materials are used in
High resistivity materials are used in
A highly conductive material must have
A highly conductive material must have
Spark plug makes use of which of the following materials for insulation ?
Spark plug makes use of which of the following materials for insulation ?
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
Low resistivity materials are used in
Low resistivity materials are used in
In conductors conduction of electricity takes place due to movement of
In conductors conduction of electricity takes place due to movement of
The co-ordination number of a simple cubic structure is
The co-ordination number of a simple cubic structure is
Piezoelectric materials serve as a source of ________ .
Piezoelectric materials serve as a source of ________ .
The transition temperature of mercury is
The transition temperature of mercury is
Which of the following material is not a semiconductor ?
Which of the following material is not a semiconductor ?
Platinum is used in
Platinum is used in
The carbon percentage is least in
The carbon percentage is least in
Carbon electrodes are not used in
Carbon electrodes are not used in
Is the property of absorbing moisture from atmosphere.
Is the property of absorbing moisture from atmosphere.
A perfect conductor has
A perfect conductor has
_________ is most commonly used for making magnetic recording tape
_________ is most commonly used for making magnetic recording tape
Selenium is _____ semiconductor.
Selenium is _____ semiconductor.
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 ?
Superconducting metal in super conducting state has relative permeability of
Superconducting metal in super conducting state has relative permeability of
Commonly used conducting materials are
Commonly used conducting materials are
The conduction of electricity, in semiconductors, takes place due to movement of
The conduction of electricity, in semiconductors, takes place due to movement of
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 ?
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
Is an element used in semiconductors whose atoms have three valence electrons.
Is an element used in semiconductors whose atoms have three valence electrons.
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
The structure sensitive property of a super conductor is
The structure sensitive property of a super conductor is
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
Superconductors are becoming popular for use in
Superconductors are becoming popular for use in
For germanium the forbidden energy gap is
For germanium the forbidden energy gap is
Carbon bearings are used under which of the following conditions ?
Carbon bearings are used under which of the following conditions ?
In thermocouples which of the following pairs is commonly used ?
In thermocouples which of the following pairs is commonly used ?
Is viscoelastic.
Is viscoelastic.
The impurity atoms is semiconductors
The impurity atoms is semiconductors
A carbon resistor contains
A carbon resistor contains
The forbidden gap in an insulator is
The forbidden gap in an insulator is
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 affect greatly the resistivity of electrical conductors?
Which of the following affect greatly the resistivity of electrical conductors?
The covalent bond is formed by
The covalent bond is formed by
Which of the following materials is the best conductor of electricity ?
Which of the following materials is the best conductor of electricity ?
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.
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.
The value of critical field below the transition temperature will
The value of critical field below the transition temperature will
The resistivity of a metal is a function of temperature because
The resistivity of a metal is a function of temperature because
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 ?
For a hole which of the following statements is incorrect ?
For a hole which of the following statements is incorrect ?
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?
__________ is the main constituent of glass
__________ is the main constituent of glass
The kinetic energy of a bounded electron is
The kinetic energy of a bounded electron 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
_______ is an example of piezoelectric material.
_______ is an example of piezoelectric material.
Which of the following is a semiconductor material ?
Which of the following is a semiconductor material ?
Carbon rods are used in wet and dry cells because
Carbon rods are used in wet and dry cells because
Surface resistance of an insulating material is reduced due to the
Surface resistance of an insulating material is reduced due to the
________ has the best damping properties.
________ has the best damping properties.
The conductivity of an extrinsic semiconductor with temperature
The conductivity of an extrinsic semiconductor with temperature
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 ?
Most of the common metals have _________ structure.
Most of the common metals have _________ structure.
_______ has zero temperature co-efficient of resistance.
_______ has zero temperature co-efficient of resistance.
The conductivity of a metal is determined by
The conductivity of a metal is determined by
Which of the following variety of copper has the best conductivity ?
Which of the following variety of copper has the best conductivity ?
Overhead telephone wires are made of
Overhead telephone wires are made of
_______ is a hard solder.
_______ is a hard solder.
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
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
Steel wire is used as
Steel wire is used 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
The converse of hardness is known as
The converse of hardness is known as
Solder is an alloy of
Solder is an alloy of
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 ?
Mercury as an electric contact material is
Mercury as an electric contact material is
Which of the following are non-conductors of electricity?
Which of the following are non-conductors of electricity?
An H.R.C. fuse is
An H.R.C. fuse is
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.
