Engineering Materials - Electronics Engineering test questions

Engineering Materials - Electronics Engineering test questions


(1) The variety of copper that has the best mechanical strength is

(A) Soft copper
(B) Cast copper
(C) Hard drawn copper
(D) Annealed copper

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ANSWER: Hard drawn copper




(2) Aluminium ore is known as

(A) Bauxite
(B) Alum
(C) Hamaetite
(D) Galena

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ANSWER: Bauxite




(3) At absolute zero resistivity of copper is

(A) 3.56 μ ohm-cm
(B) 2.56 μ ohm-cm
(C) 1.56 μ ohm-cm
(D) Negligibly small

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ANSWER: Negligibly small




(4) The minimum cross-section required for an aluminium conductor to carry an electric current of 75 A is

(A) 30 mm²
(B) 25 mm²
(C) 20 mm²
(D) 100 mm²

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ANSWER: 25 mm²




(5) In case of face centered cubic lattice, the atomic radius is

(A) a√3/4
(B) a√3/5
(C) a/3
(D) a/2

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ANSWER: a/2




(6) Constantan contains

(A) Silver and tin
(B) Tungsten and silver
(C) Copper and nickel
(D) Copper and tungsten

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ANSWER: Copper and nickel




(7) German silver is an alloy of

(A) Copper, zinc and nickel
(B) Silver, tin and tungsten
(C) Copper, manganese and nickel
(D) None of the above

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ANSWER: Copper, zinc and nickel




(8) If the resistance of a conductor does not vary in accordance with the ohm’s law it is known as

(A) Non conductor
(B) Non-linear conductor
(C) Reverse conductor
(D) Bad conductor

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ANSWER: Non-linear conductor




(9) An e.m.f. is observed to exist between the two ends of a piece of metal that is made to have a temperature gradient. This phenomenon is known as

(A) Kelvin effect
(B) Peltier effect
(C) Seebeck effect
(D) Thomson effect

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ANSWER: Thomson effect




(10) Which one of the following exhibits the same elastic properties in all directions?

(A) Isentropic
(B) Visco elastic
(C) Isotropic
(D) Inelastic

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ANSWER: Isotropic




(11) _____________ is a ceramic material

(A) MgO
(B) Invar
(C) Leather
(D) Nylon

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ANSWER: MgO




(12) _____________ is generally used in appliances with heating elements

(A) Clad metal type of thermostat
(B) Magnetic type of thermostat
(C) Circuit breaker type of thermostat
(D) Bimetallic type of thermostat

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ANSWER: Bimetallic type of thermostat




(13) Bakelite is

(A) Highly inflammable
(B) A semiconductor
(C) Uncombustible
(D) Low resistance conductor

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ANSWER: Uncombustible




(14) In spark plugs, insulating material used is

(A) Porcelain
(B) Polysterene
(C) Rubber
(D) Mica

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ANSWER: Porcelain




(15) In thermocouples, the materials that are commonly used in pairs are

(A) Silver – German silver
(B) Copper - constantan
(C) Aluminium - tin
(D) Iron - steel

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ANSWER: Copper - constantan




(16) The value dielectric constant for most of the solid substances is

(A) Nearly 100
(B) More than 20
(C) Less than 1
(D) Between 1 and 10

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ANSWER: Between 1 and 10




(17) The property of materials by which they can be drawn into wires is known as

(A) Creep
(B) Elasticity
(C) Ductility
(D) Malleability

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ANSWER: Ductility




(18) For Rohelle salt, the Curie point is about

(A) 240° C
(B) 250° C
(C) 1000° C
(D) Absolute zero

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ANSWER: 240° C




(19) ____________ can be used for temperatures upto 500° C.

(A) Polythene
(B) Paper-oiled
(C) Empire cloth
(D) Mica

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ANSWER: Mica




(20) A small changes in dimensions occur when a ferromagnetic substance is magnetized. This phenomenon is called

(A) Magnetic expansion
(B) Magnetostriction
(C) Magnetic hysteresis
(D) Magneto-calorisation

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ANSWER: Magnetostriction




(21) When 0.3% to 4.5% of silicon is added to iron then

(A) It reduces the saturation magnetization
(B) It increases the hysteresis loss
(C) It increases the electrical resistivity of iron
(D) None of the above

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ANSWER: It increases the electrical resistivity of iron




(22) The household glass that is commonly used is

(A) High silica glass
(B) Soda lime glass
(C) High leaded glass
(D) Boro silicate glass

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ANSWER: Soda lime glass




(23) __________________ polymer is crystalline

(A) Polyvinyl chloride
(B) Polyethylene
(C) Polymethyl metacrylate
(D) Polyvinylidene chloride

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ANSWER: Polyethylene




(24) An alloy containing 71% copper, 28% zinc and 1% tin is known as

(A) Admirality brass
(B) Muntz metal
(C) Alpha brass
(D) Cartridge brass

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ANSWER: Admirality brass




(25) Which one of the following is piezo-electric material?

(A) Polysterene
(B) Corrundum
(C) Silica sand
(D) Quartz

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ANSWER: Quartz




(26) Overhead telephone wires are

(A) Aluminium wires
(B) ACSR conductors
(C) Steel wires
(D) Copper wires

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ANSWER: Steel wires




(27) The property of the best damping is found in

(A) High speed steel
(B) Cast iron
(C) Diamond
(D) Mild steel

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ANSWER: Cast iron




(28) The ability of material to absorb a large amount of energy is

(A) Resilience
(B) Toughness
(C) Ductility
(D) Malleability
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ANSWER: Resilience




(29) For elastic materials stress and strain are related by

(A) Dalton’s law
(B) Hooke’s law
(C) Gauss’s law
(D) Poisson’s law

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ANSWER: Hooke’s law




(30) The permeability and permittivity of a medium are

(A) Related by the velocity of electromagnetic waves
(B) Related by the Boltzmann’s constant
(C) Related by atomic number
(D) Independent of each other

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ANSWER: Independent of each other




(31) In standard resistance coils and in instrument shunts, the material used is

(A) Magnanin
(B) Almico
(C) Nichrome
(D) Graphite

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ANSWER: Nichrome




(32) Wear resistance of a material depends on

(A) Hardness
(B) Tensile strength
(C) Poisson’s ratio
(D) Elasticity

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ANSWER: Hardness




(33) Ordinary soft solders usually melt at temperatures

(A) Nearly room temperatures
(B) At 0°C
(C) Below 200°C
(D) Above 300°C

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ANSWER: Below 200°C




(34) Sulphur hexafluoride is used for

(A) Synchronous motors
(B) Switch gears
(C) Dynamos
(D) DC series motors

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ANSWER: Switch gears




(35) The property that has lower value for copper as compared to aluminium is

(A) Melting point
(B) Resistivity
(C) Specific gravity
(D) All of the above

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ANSWER: Resistivity




(36) In case of BCC crystals the packing fraction is

(A) 0.74
(B) 0.93
(C) 0.56
(D) 0.68

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ANSWER: 0.68




(37) Which of the following is the unique characteristic possessed by a perfect black body?

(A) A good radiator
(B) A good absorber
(C) Neither a good radiator nor a good absorber
(D) A good absorber and a good radiator

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ANSWER: A good absorber




(38) When two metals that have different expansion coefficients are rolled together into strips, the composite product is known as

(A) Clad metal
(B) Cold rolled metal
(C) Bimetal
(D) Eutectic

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ANSWER: Bimetal




(39) Find the odd one out

(A) Polyster
(B) Acetal
(C) Nylon
(D) Polyurethane

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ANSWER: Polyster




(40) The atomic number of the element whose outermost electrons fill 3 – p sub-shells will be

(A) 20
(B) 16
(C) 24
(D) 18

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ANSWER: 18




(41) As temperature is lowered, the resistivity of all normal metals

(A) Tends to a constant value
(B) At first decreases and then increases
(C) Tends to zero
(D) At first increases and then decreases

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ANSWER: Tends to zero




(42) Consider two iron pieces A and B at temperatures T1 and T2 respectively. When placed in dark, A appears red and B appears yellow. The relation between temperatures T1 and T2 is given by

(A) T1(B) T1(C) T1=T2
(D) None of the above

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ANSWER: T1




(43) Figure of merit is used to

(A) Measure the extent of doping of intrinsic semiconductors
(B) Compare the efficiency of thermoelectric materials
(C) Compare the extent of purity of semiconductor materials
(D) All of the above

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ANSWER: Compare the efficiency of thermoelectric materials




(44) In solid argon, the type of bonding that exists is

(A) Vander Waals
(B) Ionic
(C) Covalent
(D) Mixture of covalent and Vander Waals

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ANSWER: Vander Waals




(45) The ruby rod used for lasers is made of

(A) Aluminium oxide
(B) Germanium
(C) Copper
(D) Silica

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ANSWER: Silica




(46) _______________ method can be used for thermoplastic materials

(A) Compression moulding
(B) Casting
(C) Blow moulding
(D) Calendering

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ANSWER: Calendering




(47) For face centered cube, the atomic packing factor is

(A) 0.14
(B) 0.74
(C) 0.66
(D) 0.54

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ANSWER: 0.74




(48) Charpy test is associated with

(A) Brittleness
(B) Hardness
(C) Wire drawing
(D) Malleability

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ANSWER: Brittleness




(49) Cadmium is added to copper primarily to

(A) Reduce cost
(B) Increase mechanical strength
(C) Improve resistivity
(D) None of the above

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ANSWER: Increase mechanical strength




(50) Rutile is

(A) Crystal with three equal axes not at right angles
(B) A discrete unit of energy
(C) Most common phase of TiO2
(D) Polymeric material

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ANSWER: Most common phase of TiO2




(51) For Brinell hardness test

(A) A ball of 1.587 mm is used
(B) A ball of 10 mm diameter is used
(C) A diamond cone of 120° is used
(D) A diamond cone of 136° is used

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ANSWER: A ball of 10 mm diameter is used



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