Objective type questions
Sub: Material Science
UNIT 1:


*( Answers are given after all questions )*

1. Consider a parallel plate capacitor having the area of each plate a m2 and distance between plate is d mts. The dielectric medium between is plate is vacuum. Then the capacitance C0 is given by,
C0 = ad/€0
C0 = d/a€0
C0= d€0/a
C0= a€0/d
2. The relation between electric field density D & electric field intenisty E and absolute permittivity € is 
D=€E
€=E/D
€=D/E
Both (a) and (c)
3. …………are the phenomenon of interest and they are studied as function of frequency and of temperature
Polarization
Dielectric strength
Dielectric loss
Both (a) and (c)
4. In the given below statement which of the followin is correct
Orientation polarization is directly proportional to temperature and inversely proportional to square of permanent dipole moment
Orientation polarization is inversely proportional to temperature and directly proportional to square of permanent dipole moment
Orientation polarization is inversely proportional to temperature and directly proportional to square of permanent dipole moment
Orientation polarization is directly proportional to temperature and inversely proportional to square of permanent dipole moment
5. Two parallel plates 0.15*0.30 m2 in area are separated by dielectric of thickness0.06m dielectric constant €r=5.4. the capacitor formed is connected to 400 V dc supply. Calculate the capacitance of capacitor
3.585*10-11 F
35.85*10-11 F
0.3585*10-11 F
3.585*10-12 F
6. Photoelectric cells have following types
Photoemissive cells
Photoconductive cells
Photo voltaic cells
All of the above
7. When the photoemissive cells emit the photo electrons 
Frequency of light is greater than threshold frequency
Frequency of light is equal to threshold frequency
Frequency of light is lesser than threshold frequency
Both (a) and (b)
8. Following are the desirable properties of photoconductive material
Higher photoconductive gain
Lesser noise
Higher quantum efficiency
All the above
9. The material in which …………… effects are important are called dielectrics 
Dipole moments
Polarization
Dielectric loss and loss tangent
Dielectric strength
10. Assumptions in Clausius Mosotte Equation are 
Equation is applicable to elemental solid dielectrics only having cubic crystal structure
The polarizability of molecule is isotropic
Arrangement of molecules is isotropic
All of the above
11. When charge storage in the main function of non conducting material then such material are called
Insulation
Dielectric
Either (a) or (b)
None of these
12. Which of the following is dielectric material
Paper
Mica glass
Both (a) and (b)
None of these
13. Two charges of equal magnitude but opposite polarity and separated by distance d constitute a dipole moment which is given by,
µ=q/d
µ=q*d
µ=-q*d
µ=-q/d
14. In case of …………….. the electric dipole moment is present in the absence of external electric field 
polar dielectrics
non polar dielectrics
either (a) or (b)
none of these



15. Which of the following is polar
KI
KCl
both (a)and (b)
none of these
16. Which of the following is non polar
He, Ne
N2, H2
Both (a) and (b)
None of these
17. The dielectric material which lack centre of symmetry are 
Ferroelectric
piezoelectric
Pyroelectric
Paraelectric
18. Which of these statements is true 
All the ferromagnetic materials
Exhibit piezo electric effect
Posses center of symmetry
Exhibit pyro electric effect
Exhibit spontaneous polarization
1 and 2 are correct
1, 2 & 4 are correct
2, 3 and 4 are correct
Only 3 is correct
19. The unit of polarization is 
Coul-m
Coul/m
Coul/m2
Coul/m3
20. the material that acquires spontaneous polarization is 
Ferro electric
Pyro electric
Both (a) and (b)
piezo electric
21. The transducers used in microphones are made up of 
Dielectric
piezo electric
insulator
none of these
22. The Dielectric constant at optical frequency is 
nearly zero
less than static Dielectric constant
greater than static Dielectric constant
equal to static Dielectric constant
23. The polarization is dependent upon temperature in
ionic material
non polar material
polar material
none of these
24. The loss factor in dielectric depends upon 
conductivity 
reciprocal of Dielectric constant  
thickness of dielectric
initial polarization
25. For polar material Dielectric constant   is 
unity
infinite
zero
very large
26. The common feature between ionic and electronic polarization is
polarization in both is temperature independent
polarization in both is temperature dependent
Either (a) or (b)
None of these
27. In polar liquids the Dielectric constant ………… with temperature
Increases 
Decreases
Remains constant
No relation exists
28. The dielectric constant of a dielectric …………. With increasing frequency of applied field 
Increases 
Decreases
Remains constant
No relation exists
29. Capacitor for high frequency (?) require material whose loss angel is 
High 
Low
Either (a) or (b)
None of these
30. Quartz is an example of 
Piezo electric crystal
Pyro electric crystal
Ferro electric crystal
None of these
31. Non polar molecules have ……….. structure
Symmetrical
Asymmetrical
Either (a) or (b)
None of these
32. The relaxation time is smallest for
Ionic polarization
Electronic polarization
Orientation polarization
None of these
33. Clausius Mossotti Equation is valid for ………….. dielectrics
Liquids and polar
Gases and non polar
Liquids and non polar
Gases and non polar
34. Unit of electric flux density is
V/m2
coul/ m2
V/m
none of these
35. Which one of the following is true
Ferro electric crystal gets polarized due to dipole interaction
Piezo electric crystal gets polarized by applying external stress
All ferro electric materials are piezo electric  but all piezo electric materials are not ferro electric  
All the above
36. Loss tangent i.e. tanδ depends upon 
Temperature
Frequency
Both (a) and (b)
None of these
37. Greater the value of tanδ ………….. will be dielectric loss
Larger
Smaller
Either (a) or (b)
None of these
38. The relation between dielectric power loss, frequency, supply voltage, capacitance and loss tangent
P=2πfCV/ tanδ
P=2πfCVtanδ
P=2πfCV2 tanδ
P=2πfVtanδ/C
39. A non polar molecule is one in which 
Center of gravity of nucleus or electrons are displaced
Center of gravity of nucleus or electrons are coincide
There is no magnetism
Both (b) and (c)
40) The dielectric strength ____ with increase in thickness of specimen 
      a) decrease
      b) increases 
      c) remain constant 
      d)none of them 
41) _____ is the dielectric use to make standard capacitor
      a) oil filled capacitor
      b) mica
      c) glass
      d)Bakelite 
42) Dielectric losses occurring in the form of heat is called 
      a) dissipation factor 
      b) loss tangent tan
      c) both a) & b)
      d) dielectric constant 
43) The phenomenon of emission of electron from a metal surface when light of suitable wavelength falls on it called _____.
     a) thermonic  emission 
     b) field emission 
     c)photoelectric emission
     d)secondary emission
44)_______are oftenlly referred as semiconductor device that connect       light in to DC  electricity 
Photovoltaic cell
Photoconductive cell
Photoemissive ceel 
None of this 
45) the minimum energy photon capable of raising an electron from valance band to conduction band of semiconductor of  (energy gap is E) is (vo threshold freq) h=6.66 10×-34 J sec
  a) E= hv0
  b) E=h/v0
  c) no such relation exists
  d) E=v0/h
46) Material use for polycrystalline PV cell are 
  a)  cadmium  telluride [Cd Te]
  b) copper indium dielenide [Cu In Se2]
  c) both a&b 
  d) none of these
47) photoconductive cell are used in 
  a) burglar alarms
  b) flame detector 
  c) control street light 
  d) all the above 
48) PV cell find applications in 
  a) photographic exposuremeter
  b) lighting control systems
  c) automatic 
  d) all the above 
49) The emission of electron in vaccum diode is achieve by  
a) Heating 
b) Electron bombardment 
c) Electrostatic field 
d) Magnetic field 
50) The work function for cooled emitter material is 
a)1.0ev 
b)2.63ev 
c)4.32ev
 d) 3.98ev 
51) Optical fiber use in 
a)for transmission 
b) wire breaker 
 c) frequency    
 d) none of above 
52) The resistivity of semiconductor decreases with irradiation  this principle is used in 
Photo conductive cell 
Photo emissive cell
PV cell
None of this
1. d
2.d
3.d
4.c
5.a
6.d
7.a
8.d
9.b
10.d

11.b
12.c
13.b
14.a
15.c
16.c
17.b
18.b
19.c
20.c

21.b
22.b
23.b
24.d
25.d
26.a
27.b
28.a
29.b
30.a

31.a
32.b
33.b
34.b
35.d
36.c
37.a
38.c
39.b
40.a

41.b
42.c
43.c
44.a
45.a
46.c
47.d
48.d
49.a
50.b

51.c
52.a

UNIT 2

1. The material which obstructs the flow of current without any appreciable loss of power is called ………material.
Dielectric
Insulating
Anti ferromagnetic
Superconducting
2. The insulating materials meant for most of the electronic equipment should posses
High 
Dielectric strength 
Mechanical strength 
Thermal stability 
All the above 
  3.  Exposure of insulating material to moisture causes increases in 
Dielectric loss 
Dielectric constant 
Dielectric strength 
insulating resistance 
4) surface resistivity of an insulating material is reduce _______ atmosphere .
a) humid 
b) smoky & dirty 
c) both a&b
d) none of this 
5) the electric breakdown strength of an insulating material is depends  on .
a) composition of material 
b) moisture content & temp 
c) thickness of material 
d) all of above 
6) an insulating material starts conducting when
a) temp is raised ot very high value 
b) the vtg applied increases above breakdown value 
c) either (a) or (b) 
d)none of this 
7) which one of the material have high dielectric strength
a)soft rubber  
 b) glass 
c) porcelain 
d) polysterene  
8) the capacitance per unit volume is max for 
a)air capacitor 
b) mica capacitor
c) ceramic capacitor
d)electrolyte capacitor
9)which one of the capacitor is suitable for compensation of harmonic and reactive power?
a) mica capacitor
b) glass capacitor
c) polypropylene  capacitor
d) electrolyte capacitor
10)the ceramic dielectric use in electrical engg included 
cement & silicide  
porcelain & cement 
cardeiete &  porceline 
silicide & cardierite 
11) which one of the following materials has the highest dielectric strength 
a) Polysterene  (b) Marble (c) Cotton (d) Transformer Oil
12. Which of the following insulating materials has least affinity for moisture?
Cotton
Paper
Asbestos
Mica
13. Which among the following have capacitance values from few µF to high µF?
Mica, glass, low loss ceramic
High permittivity ceramics
Paper
Electrolyte
14. The relative dielectric constant of solid dielectrics in alternating field is
Maximum at power frequency and decreases to unity at frequency in UV range
Maximum at power frequency and decreases to zero at frequency in UV range
Unity at power frequency and increaeses value at frequency in UV range
Independent of frequency variations
15. Which of the following statements is correct
Vacuum can act as dielectric material
Piezo electric material can act as a transducer
Quartz crystal is ferro electric material
The dielectric constant of dielectric depends on frequency of applied field
16. The temperature co-efficient of resistance of an insulator is
Positive and independent of temperature
Negative and independent of temperature
Negative and dependent of temperature
Positive and dependent of temperature
17. What does quality factor of dielectric mean
It is related to value of permittivity of material
It is related to breakdown voltage of dielectric
It is related to value of maximum stored energy and average power loss in dielectric 
It is related to value of resistivity of material
18.In solid or liquid dielectric with externally applied electric field as interatomic distance increases the internal field E
Increases
Decreases
Remains unaltered
Increases or decreases based on temperature
19. In case of dielectric subjected to an alternating electric field of frequency f the dielectric loss proportional to which of the following
f
f2
1/f
1/f2
20. Low current round conductor used in electric machine is covered by
PVC
Enamel
Polythene
Rubber
21. The degree of crystallinity of polymer is reduced by
Fast cooling from liquid state
Absorption of water
Slow cooling from liquid state
None of these
22. ……….. is main constitute of glass
Al2O3
B2O3
SiO2
Fe2O3
23. Line insulators are made up of 
Porcelain 
Mica
Marble 
PVC
24) Consider the following
Application of low permittivity ceramics include which of the following?
Suspenstion insulation for HV lines
Superconductors 
Pin insulators for low voltage lines 
Select the correct ans using code given below
1&2  b)1&3  c) 2&3 d) 1,2&3
25) spark plug makes use of ________ for insulation
a) mica
b) proclaim
c) asbestos 
d) glass

26) In electrical M/C varnish is manly used in__________
a) impregnation
b) coating
c) adhesion
d) all of these

27) sometimes varnish is coated on hard            insulating materials. This is done to improve
a) resistance to moisture
b) creeping discharge voltage
c) outer appearance
d) all of the above

28) At very high frequency of order of 10Hz the permittivity of dielectric is due to ___________ polarization
a) magnetic
b) ionic
c) electronic
d) non of these

29) polar dielectric are normally employed for
a) dc and power frequency
b) microwave
c) high frequency
d) non of these

30) Which of the following dielectrics is not preferred for high frequency applied ?
a) Teflon
b) butyle rubber
c) polysterene
d) polythylene

31) Which of the following is polar dielectric?
a) Teflon
b) polyethelene
c) nylon
d) quartz

32) Which of the following is non polar dielectric?
a) polysterene
b) castar oil
c) phenolic pastics
d) non of these

33) The dielectric loss occurs in all solid and liquid dielectric due to
a) Hysterisis
b) conduction
c) both a&b
d) non of the above

34) The dielectric susceptibility determines the value of
a) dielectric strength 
b) dielectric permittivity
c) both a&b
d) non of these

35) The possible breakdown in solid dielectric may be
a) electrothermal
b) elctrochemical
c) purely electrical
d) all of these

36) The power arc following a flash over on the breaking of contacts over the insulation surface puts the surface to
a) Chemical action
b) Extreme heat
c) Deposition of electrode material
d) all of the above

37) Insulation used in commutators is _________
a) mica
b) wood
c) PVC
d) glass

38) Which one of the following gases is classified as electronegative?
a) SF6
b) methane
c) ethane
d) nitrogen

39) Dielectric strength of SF6 is about__________ times of an air
a) 2.5
b) 4.5
c) 6.5
d) 7.5

40) SF6 is used in
a) Power transformer 
b) switch gears
c) synchronous alternator
d) synchronous motors

41) Consider the following statements
An insulating material shows polarization due to charge atoms 
Its polarizibility
Decreases with applied electric field
Remains independent of temperature at give field
Increases with applied electric field at constant temperature
Which of the following are correct?
1onely b) 1&2 only  c)3 only  d)2&3 only
Ans: c
42) Which one of the following is not true for SF6 gas ?
a) It is electronegative in nature
b) it has high dielectric strength
c) it is non non toxic
d) it is highly inflammable

43) The insulating material for cable should be
a) acid proof
b) non inflammable
c) non hygroscopic
d) all the above

44) Dielectric strength of paper is
a) 2-4kv/mm
b) 4-10kv/mm
 c) 12-15kv/mm
d) 15-20kv/mm

45) Insulating material have
a)a full valence band
b) an empty conduction band
c) a large energy band
d) all of the above

46) Current growth equation considering primary ionization is given by_____________
a)
b)
c) 
d) None of these

48) Technically pure liquid insulating materials are those
a) which contains solid impurities, water particals &gases
b) which are free from solid impurities
c) which are free from solid impurities and moisture
as well as gases
Non of above

49) __________ dielectric material recovers its dielectric strength partially after its breakdown
a) solid
b) gaseous 
c) liquid
d) both a&b

50) __________ dielectric material cannot be used after its breakdown
a) solid
b) liquid 
c) gaseous
d) all of the above
1.b
2.d
3.a
4.c
5.d
6.c
7.a
8.d
9.d
10.b

11.a
12.d
13.d
14.a
15.c
16.c
17.c
18.b
19.a
20.b

21.a
22.c
23.a
24.b
25.d
26.d
27.d
28.c
29.a
30.b

31.c
32.a
33.c
34.b
35.d
36.d
37.a
38.a
39.a
40.b

41.c
42.d
43.d
44.b
45.d
46.a
47.b
48.b
49.c
50.a

Unit-3

1) Magnetostriction
a) induced magnetism
b) volume changes accompanying magnetization
c) rate of magnetization
d) rate of loss of magnetization
2) Ferrites are 
a) ferromagnetic materials 
b) ferroelectric materials 
c) ferimagnetic materials 
d) antiferromagnetic materials
3) For which of the following materials the magnetization is not linearly related to applied field?
a) ferromagnetic material
b) antiferromagnetic materials 
c) ferromagnetic material
d) all of above
4) For which of the following materials the net magnetic moment is zero?
a) ferromagnetic materials 
b) paramagnetic materials 
c) antiferromagnetic materials
d) ferrimagnetic materials


5) A magnetic material above curie point exist as
a) diamagnetic
b) ferromagnetic
c) paramagnetic
d) ferrite
6) The magnetic in which permanent magnetic moment due to electron spin are already aligned due to bonding force is known as 
a) ferromagnetic materials
b) ferromagnetic materials 
c) paramagnetic materials 
d) diamagnetic materials
7) In which of the following materials the interaction between the neighboring dipoles is negligible?
a) ferromagnetic materials
b) ferromagnetic materials 
c) paramagnetic materials 
d) diamagnetic materials
8) Behavior like semiconductor can be expected from
a) ferromagnetic materials
b) ferromagnetic materials 
c) paramagnetic materials 
d) diamagnetic materials
9) ferrites are
a) not easily machinable 
b) hard materials
c) brittle materials
d) materials possessing all of the above properties
10) ferrimagnetic materials generally find applications as 
a) conductors
b) insulators
c) resistors
d) semiconductors
11) The relative permeability of superconducting matrials is
a) infinitely large 
b) normal 
c) one
d) zero
12) Above the curie temperature the _________ have no ferroelectric properties and become ordinary materials
a) conducting materials 
b) semiconducting materials 
c) insulating materials
d) non of the above
13) All magnetic materials loss their magnetic properties when
a) cooled to low temperature
b) heated to high temperature
c) kept in Al box
d) keptin vaccum

14) Bohr magnetron is a unit of 
a) magnetic energy
b) permanent dipole moment due to spin
c) polarizibility
d) hysteresis loss
15) The magnetic field required to reduce the residual magnetization to zero is called 
a) retentivity 
b) coercivity
c) hysteresis
d) saturation magnetisation 
16) consider the following statements 
Permanent magnet dipole in matter result from 
1) Orbital angular momentum of electron
2)  electron spin angular momentum
3) nuclear spin angular momentum
Which of the following statement is correct?
1&2  
 1&3  
 2&3  
 1,2&3
17) Consider the following statement regarding magnetic material
 1) Relative permeability of water is 0.99999 & that of oxygen is                                                     1.00002  hence water is diamagnetic & oxygen is paramagnetic material.
2) Ferromagnetic material has no eddy current loss.
3) Permalloy & alnico are two examples of hard magnetic materials.
4) The magnetization & applied electric field in ferromagnetic material are related nonlinearly.
Which of the statements given above are correct? 
1,2&3  
 2,3&4   
 1,3&4 
 1,2&4
18) What is a material with equal, anti parallel atomic magnetic moments known as _____________
a) Ferrimagnetic  
b) ferrite 
c) Ferromagnetic 
d) Anti ferromagnetic
19) Which one of the following is temp. below which contain materials are anti ferromagnetic & above which they are paramagnetic?
a) curie temp. 
b) ned temp. 
c) Transition temp. 
d) Weiss temp 
20) The spins in a ferromagnetic material are 
a) all aligned parallel
b) Partially aligned anti parallel without exactly cancelling out sub lattice magnetism  
c) Randomly coreeneted
d) All aligned anti parallel such that the sub lattice magnetism cancels out exactly
21) with increase in temperature magnetic susceptibility of ferromagnetic material will
C) Increases initially and then decreases
D) remains constant
22) Increases in percentage of carbon in carbon steel
a) resistivity
b) coercieve force
c) permeability
d) retentively
23) _________is the most detrimental implicitly in magnetic materials
a) sulphur
b) carbon
c) nitrogen
d) non of these
24) Unaxial anisotropy can be induced in bulk material by
a) magnetic annealing
b) magnetic quenching
c) cold working
d) any of the above method
25) Practically all organic substances are_________material
a) paramagnetic
b) diamagnetic
c) ferromagnetic
d) ferimagnetic
26) In a diamagnetic material, the effect an applied magnetic field is that
a) There is net reduction in flux density
b) The induced magnetization is in opposition to the applied field
c) a net dipole moment is induced in material
d) all of the above
27) The phenomenon by which a ferromagnetic material is magnetized
to its final state by a magnetic field is attributed to
a) eddy current and magnetic viscosity
b) magnetic viscosity and hysteresis
c) hysteresis and eddy currents
d) ageing and magnetic viscosity
28) which one of following statement is the correct statement ?
Decreasing the process of magnetization of ferromagnetic material the magnetic domains
a) only expand
b) rotate first and then expand
c) expand first and then rotate
d) neither rotate nor expand
29) A large value of exchange interaction energy in ferromagnetic material implies
a) large saturation magnetization
b) high curie temperature
c) high melting point
d)  large diamagnetic susceptibility
30) metallic copper is
a) paramagnetic substances
b) diamagnetic substances
c) ferromagnetic substances
d) ferrimagnetic substances
31) Susceptibility of diamagnetic material is
1) negative
2) positive
3) dependent on temperature
4) independent on temperature
select the correct ans using the code given
a)1&3  
b)2&4  
c)1&4  
d)2&3
32) Which of the following statement is/are correct
a) Ferromagnetic substances have very large negative value of susceptibility
b) diamagnetic substances have very small negative value of
susceptibility
c) paramagnetic substances have very small positive value of
susceptibility
d)
select the correct ans using the code given
a) 1&4  
b) 2&3  
c) 3&4  
d) 4 alone
33) Ferrites can be considered as mixed oxides of metals A & B having increase spinal structure. There formula can be written as
a) ABO2
b) A2BO2
C) AB2O 3
D) AB2O 4
34) Soft iron is used in the manufacture of electromagnets because of its
a) high saturation magnetization only
b) low retentivity only
c) low coerceive field only
d) high saturation magnetization low retentivity & low coerceive field
35) Which one of the following classes of materials can be categorized as ferites?
a) plastics
b) metals
c) alloys
d) ceramics
36) High frequency transformers core are generally made of 
a) cast iron
b) mu-metal
c) ferrite
d) graphite
37) Which one of the following statement is correct?
A ferrite core has lower specific eddy current as compared to an iron core because the ferrite core has
a) higher electrical resistance
b) lower electrical resistance
c) higher permeability
d) lower permeability
38) The hysteresis loop for material of core of transformer should be
a) short and narrow
b) tall and narrow
c) short and wide
d) tall and wide
39) The change in dimensions during the process of magnetizations termed as
a) skin effect
b) magnetostriction
c) hall effect
d) peltrs effect
40) Which one of the following have max permeability?
a) grain oriented Si steel
b) 4% Si steel
c) pure iron 
d) non of these
41) Area of hysteresis loop represents
a) copper loss 
b) eddy current loss
c) hysteresis loss
d) iron loss
42) Silicon content in steel reduces
a) hysteresis loss
b) eddy current loss
c) copper loss
d) iron loss
43) Which one of the following is correct?
Ferites are practically suited for high frequency applied because of their
a) Low distortion
b) low eddy current loss
c) high conductivity
d) high mobility
44) Air exhibits
a) ferromagnetism
b) paramagnetism
c) antiferomagnetism
d) ferrimagnetism
45) soft magnetic materials is 
a) tungsten steel
b) alco max
c) bismuth
d) iron
46) Which one of the following material is not permanent magnetic material?
a) chromium steel
b) silicon iron
c) cobalt steel
d) alnica
47) _________ causes magnetic ageing
a) mechanical magnetic & temperature condition
b) presence of strong external fields
c) variation of external magnetic circuits
d) all of the above
48) For magnetic material magnetic field density (B) & magnetic field intensity (H) is
a) directly drop
b) indirectly drop 
c) constant
d) no relation exists
49) The magnetic flux density B is given as_________
   Where Φ= magnetic flux; A= Area.
a) B=Φ/A
b) B=A/Φ
c) B=Φ×A
d) None of this
50) When the dipole moment is between paramagnetic & ferromagnetic material. They are called____________
a) ferromagnetic
b) ferrites
c) diamagnetic
d) both a & b

1.b
2.c
3.a
4.c
5.c
6.a
7.
8.b
9.d
10.d

11.d
12.c
13.b
14.b
15.b
16.d
17.a
18.d
19.b
20.b

21.b
22.d
23.b
24.d
25.b
26.
27.b
28.c
29.a
30.b

31.c
32.b
33.d
34.c
35.d
36.c
37.a
38.b
39.b
40.a

41.c
42.a
43.b44.b
44.b
45.b
46.b
47.d
48.a
49.a
50.d

Unit 4

On which of the following factors does the resistivity of material depend?
Resistance of the conductor
Area of conductor section
Length of conductor
All of above

A perfect conductors is______________
Zero conductivity
Unity conductivity
Infinite conductivity
None of above
The metal having the lowest temp. coeff. Of resistance is ______________
Gold
Copper
Aluminum
Kanthal

Commonly used conducting materials are___________
Copper
Aluminum
Both a & b
Copper and silver

Which of the following material is preferred for transmitting electrical energy over long distance?
Copper 
Aluminum
Steel reinforced copper
Steel reinforced aluminum

The conducting of conductor can be increased by
 a) decreasing its temperature
b) increasing its temperature
c) decreasing its vibration
d) increasing its vibration

7) A highly conductive material must have
a) highest conductivity
b) lowest temperature coefficient
c) good mechanical strength
d) all of the above
8)Which of the following resistance materials have the lowest temperature coefficient of resistance?
a) nichrome
b) constantan
c) kanthal
d) molybdenum
9. The conductors have transport phenomenon of electrons due to
Electric field
Magnetic field
Electromagnetic field
None of the above
10. Which of the following variety of Copper has the best conductivity?
Induction hardened copper
Hand drawn copper
Fuse annealed copper
Copper containing traces of Silicon
11. Constantan contains
Silver & Tin
Copper & Tungsten
Tungsten & Silver
Copper & Nickel
12. Which of the following is the (?) conductor of electricity?
Carbon
Steel
Silver
Aluminium
13. ............... has zero temperature co-efficient of resistance
Aluminium
Carbon
Porcelain
Manganin
14. In thermocouples which of the following pairs is commonly used?
Copper-Constantan
Aluminium-Tin
Silver-German Silver
Iron steel
15. A good electric contact material should have all of the following properties except
High resistivity
high resistance to corrosion
good thermal conductivity
High melting point
16. The conductivity of a metal is determined by 
The electronic configuration and mobility of free electrons
The number of valence electrons per atom
Either (a) or (b)
None of the above
17. Which of the following are non conductors of electricity?
Non metal solids except carbon
Air & most other gases
Pure water & liquids in general except mercury
All of the above
18. Low resistivity materials are used in 
Transformer, motor & generator windings
Transmission and distribution lines
House wiring
All of the above
19. Platinum is used in 
Electrical contacts
Thermocouple
Heating element in high temperature furnace
All of the above
20. Which of the following is an adv. of the stranded conductor over equivalent single conductor?
Less liability to kink
Greater flexibility
Less liability to break
All of the above
21. Due to which of the following reasons copper & aluminium are not used for heating elements?
Both have great tendency for oxidation
Both have low melting point
Very large length of  wires will be required
All of the above
22. Copper even though costly finds the windings of electrical machines because
Copper points offer low contact resistance
Copper can be easily soldered & welded 
Copper windings are less bulky & the machines become compact
All of the above
23. Carbon rods are used in wet & dry cells because
Carbon rods serve as conductors
Carbon can resist the attack of battery acid
Both (a) & (b)
Either (a) or (b)
24. Thermocouples are mainly used for measurement of
a) Temperature
b) Resistance current
c)eddy current
d) Coupling co-efficent
25. Due to which of the following fact in India aluminium is replacing copper?
Aluminium is more ductile & malleable than copper
Aluminium is available in plenty, cheaper & lighter than copper
Aluminium has lower resistivity than that of copper
Aluminium has less temperature co-efficient than copper
26. If the resistance of a conductor does not vary in accordance with Ohm’s Law, it is known as
Non linear conductor
Reverse conductor
Bad conductor
non conductor
27. Superconducting metal in super conducting state has relative permeability of 
Zero
One
Negative 
More than one
28. Superconductivity is observed for
Infrared frequencies
Dc & low frequencies
Ac & high frequencies
None
29. Super conductors are becoming popular for use in
Generating very strong magnetic field
Manufacture of bubble memories
Generating electrostatic field
Generating region free from magnetic field
30. The coils of dc motor starter are wound with wire of
Copper
Kanthal
Manganin 
Nichrome
31. ............ has zero temperature co-efficient of resistance
Aluminium 
Carbon
Porcelain
Manganin
32. Which of the following factors affect resistivity?
Alloying
Cold work
Temperature
All of these
33. Nichrome is an alloy of
a) Ni+Cr+Mn
Ag+Cu+Ni
Al+Sn+Cu
Cr+Mn+Cu
34. A highly conductive material should have
High conductivity
Lower RTC
Good mechanical strength
All of the above
35. The resistivity of metal is function of temperature because
The magnetic properties change with variations in temperature
The amplitude of vibrations of atoms varies with temperature
The electron density varies with temperature
None of these
36. The electrical conductivity of metals is typically of order of (Ω -1m-1)
107
10-4
105
106
37. In metals resistivity is composed of two parts: one part is characteristic of particular substance. The other part is due to 
Applied voltage
Crystal imperfection
Applied magnetic field 
Supplied thermal energy
38. Consider the following properties pertaining to an alloy used as precision resistor
1) Uniform resistance
2) Stable resistance
3) Zero or low temperature co-efficient of resistivity.
Which of these properties are desirable?
1,2 & 3
1 & 2
1 & 3
2 & 3
39. Which one of the following is correct? As frequency increases the surface resistance of metal
Decreases
Increases
Remains unchanged
Varies in an unpredictable manner
40. Superconductivity is due to
All electrons having Fermi energy at 0° K
All electrons interacting in superconducting state
Crystal structure having no atomic vibration at 0° K
Crystal structure having infinite atomic vibration at 0° K
41. A superconductor material is
Copper
Silver
Mercury
Gold 
42. Consider the statements
Superconductivity in a material can be destroyed by
Increasing the temperature above certain limit
Applying magnetic field above certain limit
Passing  at  above a certain limit through the material
Decreasing the temperature to point below critical temperature (?)

 2, 3 & 4 are correct
1, 3 & 4 are correct
1, 2 & 3 are correct
1, 2 & 4 are correct
43. Superconductivity is destroyed
At high temperature
At high magnetic field
In presence of magnetic impurities
In all above cases
44. The correct sequence of increasing order of electrical resistivity of given material is
Diamond, doped germanium, silicon, gold
Gold, silicon, doped germanium, diamond
Gold, doped germanium, silicon, diamond
Gold, diamond, silicon, doped germanium
45. The material used for making fuse element is
Alloy of Cu and Tin
Alloy of silver and brass
Alloy of lead and tin
Alloy of Al and tin
46. The resistivity of wire material having length of 1m and diameter of 0.08mm and resistance of 95.5Ω is
4.79*10-5 Ωm
4.79*10-7 Ωm
4.79*10-6 Ωm
4.79*10-8 Ωm
47. Thermal bimetals are used in
Overload relay
Generators
Motors
None of these
48. The element of electric heater is made of 
Carbon 
Nichrome
Copper
Steel
49. ...........is the best conductor of electric current
Cu
Al
Ag
Manganin
50. Constantan consists of
Copper and Tungsten
Silver and Tin
Copper and Nickel
Tungsten and Silver

1.d
2.c
3.a
4.c
5.d
6.a
7.d
8.a
9.a
10.c

11.d
12.a
13.d
14.a
15.a
16.a
17.d
18.d
19.d
20.d

21.d
22.d
23.c
24.a
25.b
26.a
27.a
28.b
29.a
30.c

31.d
32.d
33.a
34.d
35.d
36.a
37.b
38.a
39.b
40.c

41.c
42.c
43.d
44.c
45.c
46.b
47.a
48.b
49.c
50.c