Description : n-type semiconductor is an example of (A) extrinsic semiconductor. (B) intrinsic semiconductor. (C) super conductor. (D) insulators..
Last Answer : (A) extrinsic semiconductor.
Description : Hard magnetic materials are used for making (A) Permanent magnets. (B) Temporary magnets. (C) Conductors. (D) Insulator.
Last Answer : (A) Permanent magnets.
Description : Addition of trivalent impurity to a semiconductor creates many (A) holes. (B) free electrons. (C) valance electrons. (D) bound electrons.
Last Answer : (B) free electrons.
Description : When a semiconductor is doped with a P-type impurity, each impurity atom will (A) acquire negative charge. (B) acquire positive charge. (C) remain electrically neutral. (D) give away one electron.
Last Answer : (A) acquire negative charge.
Description : The conductivity of an extrinsic semiconductor (A) decreases with temperature. (B) increases with temperature. (C) remains constant with temperature. (D) decreases and then increases with temperature.
Last Answer : (B) increases with temperature.
Description : In p-type semiconductor the majority carriers are (A) holes. (B) electrons. (C) positive ions. (D) negative ions.
Last Answer : (A) holes.
Description : Hall effect may be used for which of the following? (A) determining whether the semiconductor is p or n type. (B) determining the carrier concentration. (C) calculating the mobility. (D) All the above.
Last Answer : (D) All the above. Ans: D Determining whether the semiconductor is p or n type, determining the carrier concentration, calculating the mobility
Description : Hysteresis loss least depends on (A) Frequency. (B) Magnetic field intensity. (C) Volume of the material. (D) Grain orientation of material.
Last Answer : (D) Grain orientation of material.
Description : In a ferromagnetic material the state of flux density is as follows when external magnetic field is applied to it. (A) Increased (B) Decreased (C) Remains unchanged (D) Becomes zero
Last Answer : (C) Remains unchanged
Description : Mica is a (A) Dielectric material. (B) Insulating material. (C) Magnetic material. (D) Both insulating and dielectric material.
Last Answer : (D) Both insulating and dielectric material.
Description : The property due to which the resistance of some metal or compound vanishes under certain conditions is (A) Semi conductivity. (B) Super conductivity. (C) Curie point. (D) Magnetostriction.
Last Answer : (B) Super conductivity.
Description : Ultrasonic waves are produced by making use of - (1) ferro magnetic material (2) ferri magnetic material (3) piezo electric material (4) pyro electrical material
Last Answer : (3) piezo electric material Explanation: In most applications, ultrasonic waves are generated by a transducer that includes a piezoelectric material (crystal) that converts electrical energy (electric current) to mechanical energy (sound waves).
Description : In n type semi conductor added impurity is (A) pentavalent. (B) divalent. (C) tetravalent. (D) trivalent.
Last Answer : (A) pentavalent.
Description : A 'dielectric' is a/an ________________. A. electrical insulator B. current flow C. good conductor D. semiconductor material
Last Answer : Answer: A
Description : A semiconductor is a material with a _____________. A. conductivity higher than a normal conductor B. conductivity higher than a normal insulator C. high conductivity at low temperatures D. low conductivity at high temperatures
Last Answer : Answer: B
Description : Which of the following properties distinguish a material as conductor, insulator and semiconductor? a) Free electron charges b) Fermi level after doping c) Energy band gap d) Electron density
Last Answer : c) Energy band gap
Description : At low temperature, Lead behaves as a (1) Semi conductor (2) Super conductor (3) Insulator (4) Conductor
Last Answer : (2) Super conductor Explanation: Lead exhibit superconducting phase transitions at low temperatures of 7.2 Kelvin. This discovery was made in 1913. At this temperature (known as critical temperature), ... to a different phase of matter; this superconducting phase is described by the BCS theory.
Last Answer : (2) Super conductor Explanation: Lead exhibit super conducting phase transitions at low temperatures of 7.2 Kelvin. This discovery was made in 1913.
Description : At low temperature, Lead behaves as a : (1) Semi conductor (2) Super conductor (3) Insulator (4) Conductor
Last Answer : Super conductor
Description : Magnetic materials (A) provide path to magnetic flux. (B) are good insulators. (C) are semiconductors. (D) None.
Last Answer : (A) provide path to magnetic flux.
Description : Materials, which provide a path to the magnetic flux, are classified as (A) insulating materials. (B) semi conducting materials. (C) magnetic materials. (D) dielectric materials.
Last Answer : (C) magnetic materials.
Description : Permanent magnets are made of (A) soft magnetic materials. (B) hard magnetic materials. (C) semi conductors. (D) super conductors.
Last Answer : (B) hard magnetic materials.
Description : The critical temperature above which the ferromagnetic materials loose their magnetic property is known as (A) hysterisis. (B) Curie point. (C) transition temperature. (D) standard temperature.
Last Answer : (B) Curie point
Description : Dielectric materials are (A) Insulating materials. (B) Semiconducting materials. (C) Magnetic materials. (D) Ferroelectric materials.
Last Answer : (A) Insulating materials.
Description : Gold and silver are (A) dielectric materials (B) low resistivity conducting materials. (C) magnetic materials. (D) insulating materials.
Last Answer : (B) low resistivity conducting materials.
Description : The covers of electrical machines are made of (A) soft magnetic materials. (B) hard magnetic materials. (C) super conductors. (D) semiconductors.
Last Answer : (A) soft magnetic materials.
Description : Materials which can store electrical energy are called (A) magnetic materials. (B) semi conductors. (C) dielectric materials. (D) super conductors.
Last Answer : (C) dielectric materials.
Description : The heating elements of electric irons are made of (A) Copper. (B) Nichrome. (C) Constantan. (D) Aluminium.
Last Answer : (B) Nichrome.
Description : Tick off the material, which is different from the group (A) Constantan. (B) Manganin. (C) Nichrome. (D) Brass.
Last Answer : (D) Brass.
Description : Example of high resistivity material is (A) Nichrome (B) Silver (C) Gold (D) Copper
Last Answer : (A) Nichrome
Description : Which of the following material has the highest melting point (A) Copper. (B) Aluminium. (C) Tungsten. (D) Gold.
Last Answer : (C) Tungsten.
Description : The most malleable, ductile low resistivity material is (A) Copper. (B) Aluminium. (C) Silver. (D) Iron.
Last Answer : (C) Silver.
Description : Ferrites are (A) ferromagnetic material. (B) ferrimagnetic materials. (C) anti ferromagnetic material. (D) diamagnetic materials.
Last Answer : (A) ferromagnetic material.
Description : The material with lowest resistivity is (A) constantan. (B) silver. (C) manganin. (D) nichrome.
Last Answer : (B) silver.
Description : Property of material which allows it to be drawn out into wires is (A) Ductility. (B) Solder ability. (C) Super conductivity. (D) Malleability.
Last Answer : (A) Ductility.
Description : Stilton is a – (1) Semiconductor (2) Insulator (3) Nonconductor (4) Conductor
Last Answer : (1) Semiconductor Explanation: Silicon is a chemical element with the symbol Si and its atomic number is 14. Over 90 percent of the Earth's crust is composed of silicate minerals. Highly purified silicon is used in semiconductor electronics.
Description : In a transistor, the base is _______. (1) an insulator (2) a conductor of low resistance (3) a conductor of high resistance (4) an extrinsic semiconductor
Last Answer : (2) a conductor of low resistance Explanation: A transistor is a semiconductor device used to amplify and switch electronic signals and electrical power. It is composed of semiconductor material with at least three terminals for connection to an external circuit.
Description : Ohm's law is valid in case of – (1) semiconductor (2) conductor (3) superconductor (4) insulator
Last Answer : (2) conductor Explanation: Ohm's law states that the current through a conductor between two points is directly proportional to the potential difference across the two points. It defines the relationship between the three fundamental, electrical quantities: current, voltage, and resistance.
Description : If electrical conductivity increases with the increase of temperature of a substance, then it is a: (1) Conductor (2) Semiconductor (3) Insulator (4) Carborator
Last Answer : (2) Semiconductor Explanation: A solid substance that has conductivity between that of an insulator and that of most metals, either due to the addition of an impurity or because of temperature effects
Description : If electrical conductivity increases with the increase of temperature of a substance, then it is a (1) Conductor (2) Semiconductor (3) Insulator (4) Carborator
Last Answer : (2) Semiconductor Explanation: A solid substance that has conductivity between that of an insulator and that of most metals, either due to the addition of an impurity or because of temperature effects.
Description : A doped semiconductor is called : a) Extrinsic b) Intrinsic c) Insulator d) Conductor
Last Answer : b) Intrinsic
Description : Silicon is a (1) Semiconductor (2) Insulator (3) Nonconductor (4) Conductor
Last Answer : Semiconductor
Description : Ohm’s law is valid in case of (1) semiconductor (2) conductor (3) superconductor (4) insulator
Last Answer : conductor
Description : Describe the concept of Ferro electricity. Explain the application of Ferro electric material
Last Answer : The ferroelectric material has an electric dipole moment and it is spontaneously polarized. They have high dielectric constant which is nonlinear because it is dependent on the intensity of ... used in condensers to concentrate considerable quantities of electric energy within a small space.
Description : A semi-conductor is damaged & behaves like a conductor, on passing a strong electric current through it, because it heats up the crystals & breaks the covalent bonds resulting in __________ electrons. (A) Lack of free (B) Excess of (C) Decrease in (D) None of these
Last Answer : (B) Excess of
Description : Fire refining process is employed in case of (A) Tin (B) Copper (C) Zinc (D) Aluminium
Last Answer : (B) Copper
Description : The following type of bonding is strongly directional in solids. (A) Vander Waal's (B) Ionic (C) Metallic (D) Covalent
Last Answer : D) Covalent
Description : What is a modular system? List the important properties of a modular system.
Last Answer : Ans: A modular system consists of well defined manageable units to well defined interfaces among them. Desirable properties are Each module is a well defined subsystem useful to others Each module ... modules Modules should be easier to use than build Modules should have a simple interface
Description : State the functions of a fuse. Mention the desirable properties of fuse materials.
Last Answer : Ans: Fuse is a protective device, which consists of a thin wire or strip. This wire or strip is placed with the circuit it has to protect, so that the circuit-current flows through it. When ... silver and silver alloys are used of lower ratings. Copper alloys are used in fuses of higher ratings.
Description : Give four examples of natural insulating materials.
Last Answer : Ans: Examples of the natural insulating materials are cotton, rubber, wood, mica.