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 : 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 : 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 : 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 : 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 : Give four examples of natural insulating materials.
Last Answer : Ans: Examples of the natural insulating materials are cotton, rubber, wood, mica.
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 : 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 : 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 : The dielectric strength of transformer oil should be (A) 100 V. (B) 5 KV. (C) 30 KV. (D) 132 KV.
Last Answer : (C) 30 KV.
Description : Dielectric constant of vacuum is (A) infinity. (B) 100. (C) one. (D) zero.
Last Answer : (C) one.
Description : The dielectric constant of air is practically taken as (A) more than unity. (B) unity. (C) less than unity. (D) zero.
Last Answer : (B) unity.
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 : 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 : 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 : 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 : 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 breakdown of insulation of the cable can be avoided economically by the use of (a) inter-sheaths (b) insulating materials with different dielectric constants (c) both (a) and (b) (d) none of the above
Last Answer : (c) both (a) and (b)
Description : State failure phenomena observed in insulating material. State four reasons for failure of gaseous and solid dielectric materials.
Last Answer : Failure phenomena in insulating material means the dielectric property fails : The dielectric failure mean the dielectric strength of insulating material reduces due to high voltages or high ... 6. Due to poor maintenance of insulating material there may be possibility dielectric failure
Description : Curie-Weiss law is applicable to which of the following materials? a) Piezoelectric b) Ferroelectric c) Pyroelectric d) Anti-ferroelectric
Last Answer : b) Ferroelectric
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 : 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 : 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 : Hall effect is associated with (A) Conductors. (B) Semiconductors. (C) Thermistors. (D) Solders.
Last Answer : (B) Semiconductors.
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.
Description : What is the type of bonding in silicon? (A) Ionic. (B) Covalent. (C) Metallic. (D) Ionic + Metallic
Last Answer : (B) Covalent.
Description : Micanite is a form of (A) Built up mica. (B) Hydrated potassium aluminium silicate. (C) Magnesium mica. (D) Calcium mica.
Last Answer : (A) Built up mica.
Description : The main constituents of glass is (A) SiO2 (B) B2O3 (C) Al2O3 (D) Cr2O3
Last Answer : (A) SiO2
Description : Hard ferrites are used for making (A) Transformer cores. (B) Electrical machinery. (C) High frequency equipment. (D) Light weight permanent magnets.
Last Answer : (D) Light weight permanent magnets.
Description : Aluminium is (A) Silvery white in colour. (B) Yellow in colour. (C) Reddish in colour. (D) Pale yellow in colour.
Last Answer : (A) Silvery white in colour.
Description : The percentage of carbon in mild steel is (A) 0.08 to 0.3 % (B) 0.5 to 1.4 % (D) 2.35 % (D) 0.5 %
Last Answer : (A) 0.08 to 0.3 %
Description : The most malleable, ductile low resistivity material is (A) Copper. (B) Aluminium. (C) Silver. (D) Iron.
Last Answer : (C) Silver.
Description : The heating elements of electric irons are made of (A) Copper. (B) Nichrome. (C) Constantan. (D) Aluminium.
Last Answer : (B) Nichrome.