electrical engineering Mcqs
6501. The superconductivity is due to____________?
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A. the crystal structure having no atomic vibration at 0K

B. the electrons jump into nucleus at 0K

C. none of the above

D. all electrons interact in the super-conducting state

6504. In graphite, bonding is____________?
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A. Vander Waals

B. metallic

C. Vander Waals and covalent

D. covalent

6505. Which of the following materials is preferred for transmitting electrical energy over long distance ?
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A. Aluminium

B. Steel reinforced aluminium

C. Copper

D. Steel reinforced copper

6506. High resistivity materials are used in_____________?
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A. all of the above

B. heating elements

C. incandescent lamps

D. precision instruments

E. motor starters

6507. Commonly used conducting materials are_____________?
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A. copper

B. aluminium

C. both (A) and (B)

D. copper and silver

E. platinum and gold

6510. Mercury as an electric contact material is_______________?
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A. a liquid

B. a metal

C. a metal liquid

D. a gas

6511. Solder is an alloy of______________?
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A. nickel, copper and zinc

B. silver, copper and lead

C. copper and aluminium

D. tin and lead
6512. highest conductivity_____________?
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A. all of the above

B. easy solderable and drawable quality

C. lowest temperature co-efficient

D. good corrosion resistance

E. good mechanical strength

6513. The conduction of electricity, in semiconductors, takes place due to movement of______________?
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A. negative ions only

B. positive and negative ions

C. electrons and holes

D. positive ions only

6514. Selenium is __________ semiconductor?
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A. P-type

B. N-type

C. extrnisic

D. intmisic
6515. On which of the following factors does the resistivity of a material depend ?
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A. Length of the conductor

B. Resistance of the conductor

C. All of the above

D. Area of the conductor section

6516. Which of the following material is not a semiconductor ?
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A. Gallium-arsenide

B. Selenium

C. Germanium

D. Silica
6517. Surface resistance of an insulating material is reduced due to the______________?
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A. smoky and dirty atmosphere

B. humidity in the atmosphere

C. both (A) and (b)

D. neither (A) nor (b)

6518. ___________ has the best damping properties?
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A. Diamond

B. High speed steel

C. Mild steel

D. Cast iron
6519. Thermocouples are mainly used for the measurement of_____________?
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A. eddy currents

B. resistance

C. coupling co-efficient

D. temperature
6520. Steel wire is used as____________?
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A. core wire of ACSR

B. earth wire

C. overhead telephone wire

D. all of the above
6521. The minority carrier concentration is largely a function of_____________?
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A. temperature

B. reverse biasing voltage

C. the amount of doping

D. forward biasing voltage

6522. Carbon resistors are used extensively because they are____________?
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A. compact

B. inexpensive

C. all of the above reasons

D. easy to make

6523. _________ is an example of piezoelectric material?
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A. Glass

B. Quartz

C. Neoprene

D. Corrundum

6524. Carbon bearings are used under which of the following conditions ?
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A. Where corrosive chemical action exists

B. All of the above

C. Where high temperature exists

D. Where lubrication is difficult or im-possible

6525. __________ is a hard solder?
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A. Copper-zinc

B. Tin-lead

C. None of the above

D. Tin-silver-lead

6526. Due to which of the following fact, in India, aluminium is replacing copper ?
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A. Aluminium has lower resistivity than that of copper

B. Aluminium is available in plenty, cheaper and lighter than copper

C. Aluminium has less temperature co-efficient than copper

D. Aluminium is more ductile and malleable than copper

6527. Which of the following is a semiconductor material ?
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A. Phosphorous

B. Rubber

C. Aluminium

D. Silicon
6528. Which of the following are non-conductors of electricity?
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A. Non-metal solids except carbon

B. Air and most other gases

C. Pure water and liquids in general except mercury

D. All of the above
6529. The conductivity of a conductor can be increased by_______________?
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A. increasing its temperature

B. decreasing its temperature

C. increasing its vibration

D. decreasing its vibration

6530. A carbon resistor contains_____________?
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A. carbon crystals

B. pulverized coal

C. solid carbon granules

D. finely divided carbon black
6531. Copper, even though costly, finds use in the windings of electrical machines because_____________?
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A. copper windings are less bulky and the machines become compact

B. copper points offer low contact resistance

C. all of the above

D. copper can be easily soldered and welded

6532. _____________is viscoelastic?
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A. Cast-iron

B. Glass

C. Graphite

D. Rubber
6534. The value of critical field below the transition temperature will_______________?
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A. any of the above

B. increase

C. remain unchanged

D. decrease

6536. Most of the common metals have _________ structure?
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A. orthorhombic

B. hexagonal

C. cubic

D. linear

6537. The covalent bond is formed by_______________?
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A. none of the above

B. transfer of electrons between atoms

C. sharing of variable number of electrons by a variable number of atoms

D. sharing of electrons between atoms
6540. A good electric contact material should have all of the following properties except_____________?
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A. high melting point

B. high resistance to corrosion

C. high resistivity

D. good thermal conductivity

6541. The conductors have transport phenomena of electrons due to____________?
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A. electric field

B. none of the above

C. magnetic field

D. electromagnetic field

6542. The impurity atoms is semiconductors_____________?
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A. inject more charge carriers

B. increase the kinetic energy of valence electrons

C. reduce the energy gap

D. all of the above

6543. In a crystal, an atom vibrates at a frequency determined by_______________?
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A. the heat content of the crystal

B. the temperature of the crystal

C. the stiffness of the bonds it makes with neighbors
6544. If the resistance of a conductor does not vary in accordance with Ohms law it is known as____________?
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A. bad-conductor

B. reverse conductor

C. non-conductor

D. non-linear conductor
6545. A perfect conductor has_____________?
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A. unity conductivity

B. none of the above

C. infinite conductivity

D. zero conductivity

6546. Thermonic emission occurs in______________?
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A. vacuum tubes

B. transistors

C. ferrite cores

D. copper conductors

6547. By increasing impurity content in the metal alloy the residual resistivity always_____________?
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A. decreases

B. remains constant

C. increases

D. becomes temperature independent

6548. The converse of hardness is known as______________?
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A. softness

B. toughness

C. none of the above

D. malleability

6549. The kinetic energy of a bounded electron is______________?
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A. infinite

B. none of the above

C. greater than that of unbounded electron

D. less than that of unbounded electron

E. equal to that of unbounded electron

6550. Non-linear resistors______________?
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A. produce harmonic distortion

B. none of the above

C. follows Ohms law at low temperatures only

D. result in non-uniform heating