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 : Holes are majority carriers in (A) P-type semiconductors. (B) N-type semiconductors. (C) Insulators. (D) Superconductors.
Last Answer : (A) P-type semiconductors.
Description : Ceramics are good (A) insulators. (B) conductors. (C) superconductors. (D) semiconductors.
Last Answer : (A) insulators.
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 : 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 : Hall effect is associated with (A) Conductors. (B) Semiconductors. (C) Thermistors. (D) Solders.
Last Answer : (B) Semiconductors.
Description : All semiconductors in their last orbit have (A) 8 electrons. (B) 2 electrons. (C) 4 electrons. (D) 6 electrons.
Last Answer : (C) 4 electrons.
Description : Insulators have (A) A full valence band. (B) An empty conduction band. (C) A large energy gap. (D) All the above.
Last Answer : (C) A large energy gap.
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 : 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 : 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 : Skin depth phenomenon is found in which materials? a) Insulators b) Dielectrics c) Conductors d) Semiconductors
Last Answer : c) Conductors
Description : Czochralski method is widely used for the growth of crystal of -------------materials. a) Conductors b) semiconductors c) insulator d) conductors & insulators
Last Answer : b) semiconductors
Description : Materials exhibiting zero value of resistivity are known as ______ . (a) conductors (b) semiconductors (c) insulators (d) superconductors
Last Answer : (d) superconductors
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.
Description : Classify plastic materials into two categories, describe their important properties and give two examples of each.
Last Answer : Ans: Plastic materials can be classified into thermoplastic and thermosetting plastics. Thermoplastic materials:- The properties of these plastic materials do not change considerably if they are melted ... forming elastic threads and films. Examples are Phenol formaldehyde (Bakelite), Epoxy resins.
Description : Ferroelectric materials are characterised by (A) Very high degree of polarisation. (B) A sharp dependence of polarisation on temperature. (C) Non-linear dependence of the charge Q on the applied voltage. (D) All the above.
Last Answer : (D) All the above.
Description : Ferrites are (A) ferromagnetic material. (B) ferrimagnetic materials. (C) anti ferromagnetic material. (D) diamagnetic materials.
Last Answer : (A) ferromagnetic material.
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 : 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 : A pure semiconductor under ordinary conditions behaves like (A) a conductor. (B) an insulator. (C) a magnetic material. (D) a ferro-electric material.
Last Answer : (B) an insulator.
Description : The skin effect is a phenomenon observed in a) Insulators b) Dielectrics c) Conductors d) Semiconductors
Description : Dielectric constant will be high in a) Conductors b) Semiconductors c) Insulators d) Superconductors
Last Answer : c) Insulators
Description : Transistors are made from (a) Plastic (b) metals (c)insulators (d) doped semiconductors
Last Answer : d) doped semiconductors
Description : Substances of conductivity between 10–10 10–20 (n m )–1 are: a) Insulators b) Semiconductors c)Super conductors d)Good conductors
Last Answer : a) Insulators
Description : he substances of conductivity of the order of 10–6 – 10–4 (m)–1 are : a) Insulators b) Super conductors c) Semiconductors d)Good conductors
Last Answer : d)Good conductors
Description : Classify the solids into conductors, semiconductors and insulators on the basis of band theory of solids.
Last Answer : In conductors there is no energy gap between valance band and conduction band, they are overlapped on each other. So electrons can jump from valance band to conduction band easily and material ... band when some amount of energy is supplied to it. Therefore insulators cannot conduct the current.
Description : Name two good conductors, two good insulators, and two semiconductors.
Last Answer : In general all metals are good conductors, with silver the best and copper second.
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 : Tick of the property, which is different from the group (A) Ductility. (B) Resistivity. (C) Tensile strength. (D) Hardness.
Last Answer : (B) Resistivity
Description : Tick off the material, which is different from the group (A) Constantan. (B) Manganin. (C) Nichrome. (D) Brass.
Last Answer : (D) Brass.
Description : Semi-conductors have ________ temperature coefficient of resistance. (A) Negative (B) Positive (C) Both positive and negative (D) None of the above
Last Answer : (A) Negative
Description : Atoms with four valence electrons are good conductors. (A) True (B) False
Last Answer : (B) False
Description : Paper is hygroscopic and absorbent. (A) True (B) False
Last Answer : (A) True
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 : Example of high resistivity material is (A) Nichrome (B) Silver (C) Gold (D) Copper
Last Answer : (A) Nichrome
Description : A transistor has (A) One p-n junction. (B) Two p-n junction. (C) Four p-n junction. (D) Five p-n junction.
Last Answer : (B) Two p-n junction.
Description : Bronze is an alloy of (A) Copper and Tin. (B) Copper and Steel. (C) Copper and Mercury. (D) Copper and Aluminium.
Last Answer : (A) Copper and Tin.
Description : Which of the following material has the highest melting point (A) Copper. (B) Aluminium. (C) Tungsten. (D) Gold.
Last Answer : (C) Tungsten.
Description : Number of Terminals in a MOSFET are (A) Two (B) Three (C) Four (D) Five
Last Answer : (B) Three
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 : P-N junction is (A) a rectifier. (B) an amplifier. (C) an Oscillator. (D) a Coupler.
Last Answer : (A) a rectifier.