225+ Electrostatics Objective Questions and Answers

In this article, we shared the electrostatics objective questions and answers for electrical and electronics engineers.

Electrostatics Objective Questions

Electrostatics Objective Questions and Answers

The below list provides all the multiple-choice questions related to electrostatics.

Answers are available at the bottom of the article.

1. Which is the most superior dielectric out of the following?

A)Glass
B)Air
C)Paper
D)Bakelite

2. Which of the following statements associated with capacitors is wrong?

A)A finite amount of energy can be stored in a capacitor even if the current through the capacitor is zero, such as when the voltage across it is a constant.
B)A capacitor resists an abrupt change in the voltage across it in a manner analogous to the way a spring resists abrupt change in its displacement
C)A capacitor resists an abrupt change in the current flowing through it.
D)lt is impossible to change the voltage across a capacitor even if the current through the capacitor by a finite amount in zero time, for this requires infinite current through the capacitor.

3. Two capacitors each having capacitance C and break down voltage V are joined in series. The capacitance and break down voltage of the combination is

A)2C and V
B)C/2 and V/2
C)C/2 and 2V
D)2C and 2V

4. A capacitance of 1 μF equals

A)10-8 ​​F
B)10-12 ​​F
C)10-6 ​​F
D)10-4 ​​F

5. Dielectric constant for mica is nearly

A)1 to 2
B)100
C)3 to 8
D)200

6. The units of capacitance are

A)coulombs/volt
B)volts/coulomb
C)ohms
D)henry/Wb

7. Which of the following expression is correct for electric field strength?

A)E =​​ πD2
B)E =​​ D/ε
C)E =​​ D2
D)E = ​​πD

8. A condenser suitable for D.C. only is

A)metallic paper capacitor
B)metallic plate variable gang condenser
C)oil impregrated paper condenser
D)poled aluminium electrolytic condenser

9. Dielectric strength____ with increasing thickness

A)increases
B)decreases
C)none of these answers
D)remains unaltered

10. The force between two charges is 120 N. If the distance between the charges is doubled, the force will be

A)80N
B)15N
C)40N
D)60N

11. Which of the following capacitors will have the least variation?

A)Silver plated mica capacitor
B)None of these answers
C)Ceramic capacitor
D)Paper capacitor

12. The capacitance of a capacitor is not affected by

A)thickness of plates
B)all of these answers
C)area of plates
D)distance between plates

13. Paper condenser is

A)usually of fixed value
B)electrolytic condenser
C)always polarised
D)a variable condenser

14. In a concentric cable capacitor the diameters of the inner and outer cylinders are 3 and 10 mm respectively. If εr for insulation is 3, find its capacitance per meter.

A)118.8 pF
B)138.8 pF
C)100 pF
D)110 pF

15. Inside a charge hollow conducting sphere, the potential will be

A)Proportional to the distance from the center
B)Constant
C)None of these answers
D)Inversely proportional to the distance from the center

16. A positive and a negative charge are initially 50 mm apart. When they are moved close together so that they are now only 10 mm apart, the force between them will be

A)10 times greater than before
B)5 times smaller than before
C)25 times larger than before
D)5 times greater than before

17. A capacitance is a circuit component that opposes the change in circuit

A)impedance
B)current
C)none of these answers
D)voltage

18. The charge on an isolated conductor resides

A)none of these answers
B)inside the conductor.
C)at the conductor surface.
D)partly at the surface and partly inside the conductor.

19. In a capacitive circuit

A)an increase in applied voltage makes a capacitor charge
B)none of these answers
C)decrease in applied voltage makes a capacitor charge
D)a steady value of applied voltage causes discharge

20. The unit of dielectric strength is given by

A)​​V/m
B)​​V2/m
C)​​m/V2
D)​​m/V

21. A unit tube of flux is known as____ tube

A)Newton
B)Michale
C)Faraday
D)None of these answers

22. The total deficiency or excess of electrons in a body is known as

A)voltage
B)current
C)charge
D)potential gradient

23. The presence of an uncharged conductor near a charged one increases the

A)all of these answers
B)the potential of the charged conductor
C)charge of the charged conductor
D)the capacity of the charged conductor

24. Out of the following capacitors of identical rating which one will have the smallest dimensions?

A)Paper capacitor
B)Ceramic capacitor
C)Mica capacitor
D)Aluminum foil capacitor

25. What is the value of capacitance that must be connected in parallel with 50 pF condenser to make an equivalent capacitance of 150 pF?

A)200 pF
B)100 pF
C)150 pF
D)50 pF

26. A mica capacitor and a ceramic capacitor both have the same physical dimensions. Which will have more value of capacitance?

A)It depends on the applied voltage
B)Mica capacitor
C)Ceramic capacitor
D)Both will have identical values of capacitance

27. The units of volume charge density are

A)Coulomb /​​ meter
B)Coulomb /​​ meter2
C)Coulomb /​​ meter3
D)Coulomb /​​ meter4

28. In a multilayer dielectric material on either side of a boundary.

A)the normal component of electrical displacement is same.
B)the tangential component of electrical field is necessarily zero.
C)the normal component of electrical field is same.
D)the tangential component of electrical displacement is necessarily zero.

29. An ideal voltage source will charge an ideal capacitor

A)exponentially
B)in infinite time.
C)instantaneously.
D)none of these answers

30. A variable capacitance is one whose capacitance

A)can be changed manually or by mechanical means
B)changes with temperature
C)changes with time
D)changes with voltage

31. Which of the following statements is correct?

A)The electrolytic capacitor must be connected in the correct polarity
B)Air capacitors have a blackband to indicate the outside foil
C)Mica capacitors are available in capacitance value of 1 to 10 μF
D)Ceramic capacitors must be connected in the correct polarity

32. Tangential component of the electric field on a perfect conductor will be

A)same as the normals field component and 90° out of phase.
B)infinite.
C)zero.
D)same as the normal component but 180° out of phase.

33. In the case of a lossy capacitor, its series equivalent resistance value will be

A)large
B)zero
C)very small
D)small

34. A capacitor of 80 μF is charged to a potential difference (p.d.) of 250V. The charge acquired by it is

A)0.4 C
B)0.2 C
C)0.02 C
D)0.3 C

35. The potential inside a charged hollow sphere is

A)none of these answers
B)zero.
C)less than that on the surface.
D)same as that on the surface.

36. An, electrolytic capacitor is generally made to provide

A)fixed capacitance
B)low capacitance
C)variable capacitance
D)large value of capacitance

37. The value of one Farad in e.s.u. will be

A)3 x 1010
B)1/9 X 1010
C)1/3 X 1010
D)9 x 1011

38. One volt is the same as

A)one joule
B)one joule/coulomb
C)one coulomb
D)one coulomb/joule

39. Electric flux in coulombs emanating from any surface of a cube containing C coulombs of charge at its center is

A)Q/6E
B)4πQ/6E
C)Q/6
D)Q/4π

40. Dielectric strength of the medium

A)increases with rise in temperature
B)increases with moisture content
C)none of these answers
D)is same for all insulating materials

41. Capacity of a parallel plate condenser can be increased by

A)Decreasing the distance between the plates
B)Decreasing the thickness of the plates
C)Increasing the distance between the plates
D)Increasing the thickness of the plates

42. ____ capacitors can be used only for D.C.

A)Electrolytic
B)Mica
C)Paper
D)Air

43. The unit of capacitance is

A)ohm
B)henry
C)farad/m
D)farad

44. If a current of 2 A passes through a lamp for 200 seconds, the number of coulombs of charge passing through the lamp in that time will be

A)200 C
B)300 C
C)400 C
D)100 C

45. The relation between the breakdown voltage V and the thickness (t) of the dielectric is given by V =At2/3​​, where A is a constant depending on the nature of the medium and also on the thickness t. The above statement is known as

A)Kirchhoff’s law
B)Baur’s law
C)Faraday’s law
D)None of these answers

46. Two plates of a parallel plate capacitor after being charged from a constant voltage source are separated apart by means of insulated handles, then the

A)voltage across the plates increases
B)charge on the capacitor increases
C)voltage across the plates decreases
D)charge on the capacitor decreases

47. The relation between electric polarization and susceptibility indicates that electric polarization is

A)proportional to square root of susceptibility.
B)proportional to susceptibility.
C)inversely proportional to susceptibility.
D)independent of susceptibility.

48. If a third equal and similar charge is placed between two equal and similar charges, then this third charge will

A)move out of the field of influence of the two charges
B)not be in equilibrium
C)be in unstable equilibrium
D)remain in stable equilibrium

49. The line of force due to charged particles are

A)always curved
B)none of these answers
C)always straight
D)sometimes curved

50. The unit of electric intensity is

A)​​newton/coulomb.
B)​​joules/coulomb.
C)​​volt/meter.
D)​​both (B) and (C).

51. Electric intensity at any point in an electric field is equal to the____ at that point.

A)magnetic flux density
B)electric flux
C)potential gradient
D)none of these answers

52. In the case of a lossy capacitor, its series equivalent resistance value will be

A)negligible
B)small
C)very small
D)large

53. If three 15 μF capacitors are connected in series, the net capacitance is

A)45 μF
B)5 μF
C)50 μF
D)30 μF

54. A field line and an equipotential surface are

A)none of these answers
B)always parallel
C)inclined at any angle θ
D)always at 90°

55. Which of the following capacitors has a relatively shorter shelf life?

A)Paper capacitor
B)Electrolytic capacitor
C)Ceramic capacitor
D)Mica capacitor

56. Which of the following capacitor is preferred in the case of single-phase motor?

A)Ceramic capacitor
B)Paper capacitor
C)Electrolytic capacitor
D)Mica capacitor

57. Which one of the following statements does not state that the electrostatic field is conservative?

A)The potential difference between two points is zero.
B)The work done in a closed path inside the field is zero.
C)The electrostatic field is a gradient of a scalar potential
D)The Curl of E is identically zero

58. Three capacitors each of breakdown voltage 500 V are connected in parallel. The breakdown rating of the combination will be

A)707 V
B)1,000 V
C)2,500 V
D)500 V

59. For closer tolerances which of the following capacitors is usually preferred?

A)None of these answers
B)Paper capacitor
C)Mica capacitor
D)Ceramic disc capacitor

60. Which capacitor will be physically smaller for the same ratings?

A)Ceramic capacitor
B)None of these answers
C)Paper capacitor
D)Both will be of equal size

61. A large sphere P of radius R is charged positively. It is momentarily connected to a small sphere Q of radius r. The two spheres now have the same

A)Charge
B)Energy
C)Potential
D)Electric field

62. The capacity of a spherical conductor is 1 picofarad then its diameter would be

A)1.8 x​​meter
B)1.8 x 104 meter
C)1.8 x 103 ​​meter
D)1.8 x 1010 ​​meter

63. Dielectric strength of a material depends on

A)all of these answers
B)thickness
C)temperature
D)moisture content

64. A parallel plate capacitor has a capacitance of 10 μF. If the linear dimensions of the plates are doubled and the separation between them has also doubled the value of the capacitor would be

A)10 μF
B)5 μF
C)20 μF
D)40 μF

65. Electric potential at the center of a charged conductor is

A)Zero
B)Half of that on the surface
C)Same as that on the surface
D)Twice as that on the surface

66. A capacitor having a capacitance of 5 μF is charged to a potential difference of 10,000 V. The energy stored in the capacitor is

A)150 joules
B)200 joules
C)250 joules
D)50 joules

67. ____capacitors are used in transistor circuits.

A)Electrolytic
B)Ceramic
C)Paper
D)Air

68. What will happen to an insulating medium if voltage more than the breakdown voltage is applied to it?

A)It will get punctured or cracked
B)It will melt
C)It will become magnetic
D)Its molecular structure will get changed

69. The ratio of electric flux density to electric field intensity is called____ of the medium

A)reluctance
B)permeability
C)capacitance
D)permittivity

70. The property of a capacitor to store electricity is called its

A)none of these answers
B)capacitance
C)charge
D)energy

71. A capacitor having capacitance of 40 μF is connected across 250 V D.C. source. The charging current will be least

A)initially
B)when capacitor is almost 25% charged
C)when capacitor is half charged
D)when capacitor is fully charged

72. Which of the following statements is correct?

A)Air capacitors have a black band to indicate the outside foil
B)Ceramic capacitors must be connected in correct polarity
C)Mica capacitors are available in capacitance values of 5 to 20 μF
D)Electrolytic capacitors must be connected in correct polarity

73. The electric field at a point situated at distance cl from the straight charged conductor is

A)none of these answers
B)inversely proportional to​​ d2
C)inversely proportional to d
D)proportional to d

74. The time constant and R-C circuit may also be defined as the time during which the charging current falls to____ percent of its initial maximum value.

A)63
B)42
C)37
D)73

75. The power dissipated in a pure capacitor is

A)both proportional to applied voltage and proportional to value of capacitance
B)zero
C)proportional to value of capacitance
D)proportional to applied voltage

76. Three capacitors each of the capacity C are given. The resultant capacity 2/3 C can be obtained by using them

A)two in series and third in parallel across this combination
B)all in parallel
C)all in series
D)two in parallel and third in series with this combination

77. Dielectric strength of mica is

A)50 to 200 kV/mm
B)300 to 500 kV/mm
C)30 to 50 kV/mm
D)10 to 20 kV/mm

78. When a dielectric slab is introduced in a parallel plate capacitor, the potential difference between plates will

A)remain uncharged
B)become zero
C)decrease
D)increase

79. The dielectric constant (relative permittivity) of glass is given by

A)0.1 to 0.4
B)2.0 to 4.0
C)5 to 10
D)0.5 to 1.0

80. A dielectric material must be

A)insulator
B)resistor
C)good conductor
D)semi-conductor

81. Check the correct relation

A)Potential = capacity x charge
B)Potential = charge/capacity
C)Charge = potential/capacity
D)Capacity = potential x charge

82. It was suggested by ____that the electric field should be imagined to be divided into tubes of force containing a fixed number of lines of force.

A)Faraday
B)Newton
C)All of these answers
D)Kelvin

83. Permittivity is expressed in

A)Farad/metre
B)Weber/sq-m
C)Farad/sq-m
D)Weber/metre

84. Which of the following statement(s) is/are valid in the case of conductors in electrostatic fields?

A)All of these answers
B)The electric field intensity at the surface of a conductor is everywhere directed normal to that surface.
C)The surface of a conductor is an equipotential surface.
D)The electric field intensity inside a conductor is zero.

85. Dielectric strength of a material depends on

A)all of these answers
B)temperature.
C)moisture content.
D)thickness.

86. If AC voltage is applied to a capacitive circuit, the alternating current can flow in the circuit because

A)discharge current can flow
B)varying voltage produces the charging and discharging currents
C)of high peak value
D)charging current can flow

87. Internal heating of a capacitor is usually attributed to

A)electron movement
B)plate vibration
C)leakage resistance
D)dielectric charge

88. The condensers of 20 μF and 40 μF capacitance are connected in series across a 90 V supply.

After charging, they are removed from the supply and are connected in parallel with positive terminals connected together and similarly the negative terminals.

Then the voltage across them will be

A)60 V
B)40 V
C)90 V
D)20 V

89. When a dielectric is placed in an electric field the field strength

A)reduces to zero
B)remain unchanged
C)increases
D)decreases

90. The electric field between the two spheres of a charged spherical condenser

A)Is constant
B)Decreases with distance from the center
C)Is zero
D)Increases with distance from the center

91. ____at a point is equal to the negative potential gradient at that point.

A)Magnetic flux density
B)Magnetic flux
C)Electric intensity
D)Electric flux

92. Which of the following material has the least value of dielectric constant?

A)Paper
B)Oil
C)Glass
D)Ceramics

93. The electric field intensity at a point situated at a distanced from a straight charged conductor is proportional to

A)​​d
B)​​1/d2
C)​​1/d
D)​​d2

94. “The total electric flux through any closed surface surrounding charges is equal to the amount of charge enclosed”. The above statement is associated with

A)Coulomb’s square law
B)Maxwell’s first law
C)Gauss’s law
D)Maxwells second law

95. A medium behaves like dielectric when the

A)displacement current is much greater than the conduction current.
B)displacement current is just equal to the conduction current.
C)displacement current is almost negligible.
D)displacement current is less than the conduction current.

96. Air capacitors are generally available in the range

A)10 to 400 pF
B)20 to 100 pF
C)1 to 20 pF
D)100 to 900 pF

97. When the dielectric is homogeneous, the potential gradient is

A)any of these answers
B)zero
C)uniform
D)non-uniform

98. Inside a hollow conducting sphere

A)electric field is zero.
B)electric field changes with the magnitude of the charge given to the conductor.
C)electric field is a non-zero constant.
D)electric field changes with distance from the centre of the sphere.

99. The capacitor preferred for high-frequency circuits is

A)none of these answers
B)mica capacitor
C)air capacitor
D)electrolytic capacitor

100. Putting the plates of a charged capacitor apart

A)Decreases the potential difference
B)Does not effect potential difference
C)Increases the potential difference
D)Increases the capacitance

101. The capacitor preferred for high-frequency circuits is

A)none of these answers
B)mica capacitor
C)electrolytic capacitor
D)air capacitor

102. The dielectric strength of a medium is usually expressed in

A)​​N/mm
B)​​c/m2
C)​​kV/mm
D)​​J/mm

103. The voltage applied across a ceramic dielectric produces an electrolytic field 100 times greater than air. What will be the value of the dielectric constant?

A)200
B)100
C)50
D)150

104. Which of the following capacitors are preferred for high-frequency circuits?

A)Mica capacitor
B)none of these answers
C)Air capacitor
D)Electrolytic capacitor

105. A paper capacitor is usually available in the form of

A)rolled foil
B)tubes
C)disc
D)meshed plates

106. An electric dipole is placed in an electric field generated by a point charge

A)The net electric force on the dipole may be zero
B)The torque on the dipole due to the field may be zero
C)The net electric force on the dipole must be zero
D)The torque on the dipole due to the field must be zero

107. The direction of the lines of force at any point is the direction along which a unit ____charge placed at that point would move if free to do so

A)negative
B)both negative & positive
C)positive
D)none of these answers

108. The voltage applied across a dielectric produces an electrostatic field 50 times greater than air. The dielectric constant of the dielectric will be

A)20
B)50
C)5
D)10

109. If an ohmmeter reading immediately goes practically to zero and stays there while checking a capacitor, the capacitor is

A)short-circuited.
B)leaky.
C)open-circuited.
D)satisfactory.

110. The potential difference across a capacitor of capacitance 20 μF is increased uniformly from 0 to 240 V in 1 second. The charging current will be

A)1.2mA
B)12mA
C)9.6mA
D)4.8mA

111. Energy density in a static electric field is given by

A)W = 1/2CV2
B)W = 1/2QV
C)W = 1/2DE
D)W = 1/2∈E2V

112. The point charges Q and 2Q are placed at a distance R apart. Where should a third point charge be placed, So that it is in equilibrium

A)At a point on the left of Q
B)Between Q and 2Q
C)At a point on the right of 2Q
D)None of these answers

113. Which of the following medium will have the highest value of relative permittivity?

A)Glass
B)Mica
C)Paper
D)Water

114. If an ohmmeter reading immediately goes practically to zero and stays there, the capacitor is

A)lossy
B)charged
C)short-circuited
D)satisfactory

115. A glass slab is put within the plates of a charged parallel plate condenser. Which of the following quantities does not change?

A)Charge
B)Energy of the condenser
C)Capacity
D)Intensity of electric field

116. The dissipation factor of good dielectric is of the order of

A)0.1
B)0.02
C)0.0002
D)0.002

117. “The surface integral of the normal component of the electric displacement D over any closed surface equals the charge enclosed by the surface”. The above statement is associated with

A)Kirchhoff’s law
B)Faraday’s law
C)Lenz’s law
D)Gauss’s law

118. The electric potential due to an electric dipole of length l at a point distance r away from it will be doubled if the

A)r is halved.
B)r is doubled.
C)l is halved.
D)length l of the dipole is doubled.

119. The bridge used for the measurement of the value of the capacitance is

A)Schering bridge
B)Wien’s bridge
C)Hay’s bridge
D)Wheatstone bridge

120. ___ at a point may be defined as equal to the lines of force passing normally through a unit crosssection at that point.

A)None of these answers
B)Magnetic flux density
C)Electric flux
D)Electric intensity

121. When 4 volts e.m.f is applied across a 1 farad capacitor, it will store the energy of

A)2 joules
B)8 joules
C)4 joules
D)6 joules

122. The equipotential line due to point charge Q is

A)A straight line
B)A circle
C)A hyperbola
D)An ellipse

123. Two capacitors each having capacitance C and breakdown voltage V are joined in series. The capacitance and breakdown voltage of the combination will be

A)2 C and 2 V
B)C/2 and V/2
C)C/2 and 2 V
D)2 C and V/2

124. The capacitance G is charged through a resistance R. The time constant of the charging circuit is given by

A)RC
B)C/R
C)1/RC
D)R/C

125. If the sheet of bakelite is inserted between the plates of an air capacitor, the capacitance will

A)increase
B)become zero
C)decrease
D)remains unchanged

126. A variable capacitor of 100 μF carries a charge of 0.35 μC. The capacitance is subsequently reduced to 40 pF. The voltage appearing across the capacitor after reduction of its capacitance will be

A)2000 V
B)1500V
C)4350V
D)8750 V

127. For which of the following parameter variation, the capacitance of the capacitor remains unaffected?

A)Distance between plates
B)Area of the plates
C)Nature of dielectric
D)Thickness of the plates

128. In a capacitor, the electric charge is stored in

A)metal plates
B)none of these answers
C)both metal plates and dielectric
D)dielectric

129. Two spheres of radii r1 and r2 are connected by a conducting wire. Each of the spheres has been given a charge Q. Now

A)larger sphere will have greater potential.
B)smaller sphere will have zero potential.
C)both of the spheres will have same potential.
D)larger sphere will have smaller potential.

130. Electric field intensity is a____ quantity

A)vector
B)scalar
C)both scalar and vector
D)none of these answers

131. If the dielectric of a capacitor is replaced by a conducting material the

A)plates will get short circuited.
B)capacitor can store infinite charge
C)capacitance will become very high.
D)capacitor will get heated up owing to eddy currents.

132. Which of the following capacitors will have the least value of breakdown voltage?

A)Paper
B)Ceramic
C)Electrolytic
D)Mica

133. In a cable capacitor, voltage gradient is maximum at the surface of the

A)insulator
B)conduction
C)sheath
D)earth

134. Paper capacitors usually have tolerance of

A)±10%
B)±5%
C)±15%
D)±20%

135. A capacitor charged to 200 V has 2000 μC of charge. The value of capacitance will be

A)100 μF
B)10 μF
C)1000 μF
D)10 F

136. The dissipation factor of a good dielectric is of the order of

A)0.2
B)0.002
C)0.02
D)0.0002

137. During the dielectric breakdown of a capacitor

A)electrons are scattered.
B)electrons cease to move from one plate to another.
C)permanent conduction path is established between capacitor plates.
D)none of these answers

138. 1 volt/metre is same as

A)1 metre/coulomb
B)1 joule/coulomb
C)1 newton metre
D)1 newton/metre

139. Which medium has the least dielectric strength?

A)Glass
B)Air
C)Quartz
D)Paraffin wax

140. A potential of 400 V is applied to a capacitor, the plates of which are 4 mm apart. The strength of the electric field is

A)100 kV/m
B)10 kV/m
C)2 kV/m
D)5 kV/m

141. Fields are said to be circularly polarized if their magnitudes are

A)Equal and they differ in phase by ± 90°.
B)Unequal and they differ in phase by ±90°.
C)Equal any they are in phase.
D)Unequal and they are in phase.

142. A soap bubble is given a negative charge then its radius

A)Increases
B)Remains unchanged
C)Decreases
D)None of these answers

143. The area of plates of the parallel plate capacitor, to obtain a capacity of 0.3 x​ ​10-3 μF if they are separated by a distance of 10mm and a dielectric between them of permittivity = 2.5, will be

A)0.1​​ m2
B)0.135​​ m2
C)0.125​​ m2
D)0.235​​ m2

144. The ohmmeter reading for a short-circuited capacitor is

A)few kilo ohms
B)few megaohms
C)zero
D)infinity

145. The capacitance of a capacitor is influenced by

A)plate area
B)plate separation
C)none of these answers
D)all of these answers
E)nature of dielectric

146. The capacity of the capacitor bank used in power factor correction is expressed in terms of

A)kVA
B)volts
C)kVAR
D)kW

147. The direction of electric field due to positive charge is

A)both away from the charge and towards the charge
B)none of these answers
C)away from the charge
D)towards the charge

148. Electric displacement is a____quantity

A)none of these answers
B)scalar
C)both scalar and vector
D)vector

149. The potential gradient at which the dielectric of the condenser just gets punctured is called

A)Dielectric constant
B)Dielectric number
C)Dielectric strength
D)Dielectric resistance

150. The energy of a charged capacitor resides in

A)Neither in electric nor magnetic field
B)The magnetic field only
C)Both the electric and magnetic fields
D)The electric field only

151. The absolute permittivity of free, space is given by

A)8.854 x​​ 10-9 F/m
B)8.854 x​​ 10-10 F/m
C)8.854 x​​ 10-11 F/m
D)8.854 x​​ 10-11 F/m

152. The ability of charged bodies to exert force on one another is attributed to the existence of

A)electrons
B)electric field
C)neutrons
D)protons

153. Coulomb’s law for the force between electric charges most closely resembles with

A)Law of conservation of energy.
B)Newton’s law of gravitation
C)Gauss’s theorem.
D)Newton’s law of motion.

154. Electric field intensity between plates of a parallel plate condenser is E. Now if a dielectric of medium of dielectric constant ϵ is introduced between the plates, the electric field intensity will become

A)​​ϵE
B)​​E/​​ϵ
C)​​√(ϵE)
D)​​​​√(E/ϵ)

155. In order to remove static electricity from machinery

A)ground the framework
B)humidify the surroundings
C)insulate the machinery
D)construct insulated cabins

156. Electric intensity (E) at any point in an electric field is equal to

A)potential gradient
B)(potential gradient)2
C)(potential gradient)1/2
D)(potential gradient)1/3

157. The inverse of capacitance is called

A)reluctance
B)susceptance
C)conductance
D)elastance

158. To prevent the generation of static charges on rubber or flat leather

A)surface is moistened
B)oil compound dressing is done
C)talcum powder is sprayed on the surface
D)conductive dressing is done

159. Two conductors having the same type of charges are connected by a conducting wire. There would not be any change in the amount of charges on them if

A)They have the same amount of charge
B)They have the same shape
C)They have the same capacity
D)They have the same potential

160. Which of the following statements is incorrect?

A)The thinner the dielectric, the more the capacitance and the lower the voltage breakdown rating for a capacitor
B)A capacitor can store charge because it has a dielectric between two conductors
C)Capacitors in series provide less capacitance but a higher voltage breakdown rating for the combination
D)A six dot mica capacitor colour coded white, green, black, red and yellow has the capacitance value of 500 pF

161. The electric field inside a perfectly conducting media is

A)zero.
B)dependent upon the value of the charge.
C)none of these answers
D)infinite.

162. In a charge-free space, Poisson’s equation results in which one of the following?

A)Laplace equation.
B)Continuity equation.
C)None of these answers
D)Maxwell’s equation.

163. Across the surface of a charged conductor, the electric

A)field is continuous
B)potential is discontinuous
C)field is discontinuous
D)none of these answers

164. The ratio of the charge stored by two metallic spheres raised to the same potential is 6. The ratio of the surface areas of the sphere is

A)1/​​6
B)36
C)1/6
D)6

165. Which of the following capacitors will have the least energy stored in it?

A)A 600 pF capacitor charged to 15 kV
B)A 1 μF capacitor charged to 5 kV
C)A 20 μF capacitor charged to 400 V
D)Energy stored in each above will be same

166. The electrostatic force between two charges of one coulomb each and placed at a distance of 0.5 m will be

A)36 x 106 N
B)36 x 107 N
C)36 x 108 N
D)36 x 109 N

167. The capacitance between two plates increases with

A)larger plate area, longer distance between plates and higher applied voltage
B)larger plate area and shorter distance between plates
C)shorter plate area and higher applied voltage
D)shorter plate area and shorter distance between titen

168. In a cable capacitor, voltage gradient is maximum at the surface of the

A)sheath.
B)conductor.
C)dielectric.
D)earth.

169. A capacitor stores 0.24 coulombs at 10 volts. Its capacitance is

A)0.024 F
B)0.12 F
C)0.8 F
D)0.6 F

170. In a parallel plate capacitor, a dielectric slab is introduced. Then the

A)all of these answers
B)potential difference between the plates will decrease
C)electric intensity will decrease.
D)capacitance will increase

171. The relative permittivity has the following units

A)no units
B)Wb/m
C)m/F
D)F/m

172. “The force of attraction or repulsion between two charges Q1 and Q2 at a distanced meters apart is proportional to the product of charges and inversely proportional to the square of the distance between the two charges”. The above statement is associated with

A)Lenz’s law
B)Maxwell’s law
C)Coulomb’s law
D)Faraday’s law

173. Two metal plates distance ‘d’ apart form a capacitor of value C farads. Another metal plate of thickness d/2 and of the same area is inserted in between these two plates, the capacitance of this three plate capacitor will be

A)1/2
B)1/4
C)4
D)2

174. ___capacitors are mainly used for radio-frequency tuning

A)Mica
B)Electrolytic
C)Paper
D)Air

175. Two electrons moving parallel to each other at the same velocity will

A)repel each other with the same force when moving in the same or opposite direction.
B)repel each other less strongly when moving in same direction.
C)attract each other if they move in the same direction.
D)repel each other more strongly when moving in the same direction than when moving in opposite direction.

176. A ceramic and a mica capacitor have the same physical dimensions. Which has the higher value of capacitance?

A)Both have identical value of capacitance
B)Ceramic capacitor
C)It is not possible to conclude on the basis of information supplied
D)Mica capacitor

177. A capacitor consists of

A)two conductors separated by an insulator
B)two conductors only
C)two insulators only
D)two insulators separated by a conductor

178. ___capacitors are used for audio frequency and radio frequency coupling and tuning

A)Air
B)Ceramic
C)Mica
D)Plastic film

179. The electric field intensity at a point situated 4 meters from a point charge is 200 N/C. If the distance is reduced to 2 meters. the field intensity will be

A)400 N/C
B)600 N/C
C)1200 N/C
D)800 N/C

180. While checking a good 0.05 μF capacitor by ohmmeter, it’s reading will

A)show high resistance momentarily and then a very low resistance
B)none of these answers
C)show low resistance momentarily and back off to a very high resistance.
D)show a reading of 80 ohms

181. If the dielectric of a capacitor is replaced by a conducting material

A)the capacitor will get heated up due to eddy currents
B)the capacitor can store infinite charge
C)the capacitance value of the capacitor will shoot upto very high value
D)the plates will get short-circuited

182. Mica capacitors are characterized by all of the following except

A)accurate value
B)stable operation
C)low losses
D)low leakage reactance

183. While testing a capacitor with ohm meter, if the capacitor shows charging, but the final resistance reading is appreciably less than normal, it can be concluded that the capacitor is

A)open circuited
B)airight
C)leaky
D)short-circuited

184. The sparking between two electrical contacts can be reduced by inserting a

A)capacitor in parallel with contacts
B)none of these answers
C)capacitor in series with each contact
D)resistance in line

185. Which of the following statement is true?

A)The current in the discharging capacitor decreases constantly
B)The current in the discharging capacitor grows exponentially
C)The current in the discharging capacitor decays exponentially
D)The current in the discharging capacitor grows linearly

186. The relation between the breakdown voltage V and the thickness t of the dielectric is given as V =​​ At2/3 where A is a constant which depends on the nature and thickness of the medium. This statement is known as

A)Baur’s law.
B)Coulomb’s law.
C)none of these answers
D)Gauss’s law.

187. The breakdown voltage for paper capacitors is usually

A)more than 10000 volts
B)200 to 1600 volts
C)Option 1
D)2000 to 3000 volts

188. A conducting body has a surface charge density of a coulombs/m2, the field intensity at its surface will be

A)​​σ / ε0 εr
B)​​σ2 / ε0 εr
C)ε0 εr
D)​​σ3 / ε0 εr

189. Energy stored in the electric field of a capacitor C when charged from a D.C source of voltage V is equal to____ joules

A)​​1/2 CV2
B)​​1/2 C2V
C)​​CV2
D)​​C2V

190. The capacitor charged up to 5 ms, as per the current profile given in the figure, is connected across an inductor of 0.6 mH. Then the value of voltage across the capacitor after 1 μs will approximately be

A)18.8 V
B)23.5 V
C)-30.6 V
D)-23.5 V

191. ___ is that property of a capacitor which delays any change of voltage across it

A)Capacitance
B)Inductance
C)Potential gradient
D)None of these answers

192. For preventing the generation of static charge on rubber or flat leather

A)oil compound dressing is done.
B)any of these answers
C)surface is moistened.
D)conductive dressing is done.

193. Electric field inside a hollow metallic charged sphere is

A)decreasing towards center
B)increasing towards center
C)none of these answers
D)zero

194. Which of the following statements is incorrect?

A)The stored energy in a capacitor increases with applied voltage
B)The stored in a capacitor decreases with reduction in value of capacitance
C)A wire cable has distributed capacitance between the conductors
D)The leakage resistance of ceramic capacitors is generally high

195. When the plate area of a parallel plate capacitor is increased keeping the capacitor voltage constant, the force between the plates

A)may increase or decrease depending on the metal making up the plates.
B)decreases.
C)increases.
D)remains constant.

196. Which of the following capacitors is marked for polarity?

A)Air
B)Electrolytic
C)Mica
D)Paper

197. The unit of polarization is the same as that of

A)dielectric flux.
B)electric flux density D.
C)charge.
D)electric intensity E.

198. The time constant of an R-C circuit is defined as the time during which capacitor charging voltage actually rises to____ percent of____ its value.

A)63.2, initial
B)63.2, final
C)37, initial
D)37, final

199. Which one of the following statements is correct? On a conducting surface boundary, electric field lines are

A)neither tangential nor normal.
B)always normal.
C)always tangential.
D)at an angle depending on the field intensity.

200. The number of Faraday tubes of flux passing through a surface in an electric field is called

A)electric flux
B)magnetic flux density
C)electric flux density
D)electric charge density

201. ___ field is associated with the capacitor.

A)Both Electric and Magnetic
B)Electric
C)none of these answers
D)Magnetic

202. A positively charged glass rod attracts an object. The object must be

A)Either negatively charged or neutral
B)A magnet
C)Neutral
D)Negatively charged

203. Which of the following materials has the highest value of dielectric constant?

A)Oil
B)Glass
C)Ceramics
D)Vacuum

204. An equipotential surface is one which has all points at____ potential

A)same
B)none of these answers
C)different
D)zero

205. The electric potential due to an electric dipole at an axial point distant r from the dipole is related to r as

A)​​r1
B)​​r-1
C)​​r2
D)​​ r-2

206. The electric potential at the surface of an atomic nucleus (z = 50) of radius 9 x​​ 10-15 m is

A)80 volt
B)9 x​​ 105 volt
C)9 volt
D)8 x 106 volt

207. The phenomenon of an uncharged body getting charged merely by the nearness of a charged body is known as____

A)chemical effect
B)photoelectric effect
C)induction
D)magnetic effect

208. Which of the following is not a vector?

A)Angular momentum
B)Linear momentum
C)Electric field
D)Electric potential

209. “The surface integral of the normal component of the electric intensity E over a closed surface is equal to 1/Ε0 ​​times the total charge inside it”. The above statement is known as

A)None of these answers
B)Gauss’s theorem
C)Lenz’s law
D)Faraday’s law

210. For making a capacitor, it is better to select a dielectric having

A)low permittivity
B)high permittivity
C)permittivity same as that of air
D)permittivity slightly more than that of air

211. If three 10 μF capacitors are connected in parallel, the net capacitance is

A)20 μF
B)30 μF
C)50 μF
D)40 μF

212. The potential gradient across the material of low permittivity is____ than across the material of high permittivity.

A)none of these answers
B)both smaller and greater
C)smaller
D)greater

213. Dielectric strength of a medium

A)is not affected by the moisture content
B)decreases with the increase in thickness.
C)increases with the increase in temperature.
D)increases with moisture content.

214. A charge which when placed in a vacuum from an equal and similar charge repels with a force of 9 x 103N​​, is known as

A)coulomb
B)milli-coulomb
C)micro-coulomb
D)pico-coulomb

215. Polarization of dielectric materials results in

A)absorption of electrons.
B)production of eddy currents.
C)creation of dielectric dipoles.
D)release of protons.

216. A single core cable used of 33000 V has a conductor diameter 10 mm and an internal diameter of the sheath of 25 mm. The maximum electrostatic stress in the cable is

A)72 x 105 V/m
B)92 x 105 V/m
C)62 x 105 V/m
D)82 x 105 V/m

217. The mass of an electron is equal to

A)1.673 x 10-27 kg
B)9.11 x 10-31 kg
C)1.602 x 10-19 kg
D)9.11 x 10-20 kg

218. lf C be the capacitance, V be the potential difference and I is the current, then 1/CV will have the unit of

A)power
B)reactive power
C)frequency
D)time

219. A capacitor in a circuit became hot and ultimately exploded due to wrong connections, which type of capacitor it could be?

A)Any of these answers
B)Ceramic capacitor
C)Electrolytic capacitor
D)Paper capacitor

220. A charge q is divided into two parts q1, and (q – q1) what is the ratio q/q1 so that the force between the two parts placed a given distance apart is maximum

A)2 : 1
B)1 : 4
C)1 : 2
D)1 : 1

221. An uncharged conductor is placed near a charged conductor, then

A)the uncharged conductor is attracted first and then charged by induction
B)it remains as such
C)the uncharged conductor gets charged by conduction
D)the uncharged conductor gets charged by induction and then attracted towards the charging body

222. In a capacitor, the electric charge is stored in

A)dielectric as well as metal plates
B)dielectric
C)none of these answers
D)metal plates

223. While testing a capacitor with ohmmeter, if the capacitor shows charging but the final resistance reading is appreciably less than normal the capacitor is

A)leaky.
B)open circuited.
C)short circuited.
D)satisfactory.

224. Capacitance increases with

A)increase in plate area and distance between the plates
B)reduction in plate area and distance between the plates
C)decrease in plate area and value of applied voltage
D)increase in plate area and decrease in distance between the plates

225. The value of dielectric constant for vacuum is taken as

A)10
B)zero
C)4
D)1

226. A hollow sphere of charge does not produce an electric field at any

A)None of these answers
B)Interior point
C)Outer point
D)Surface point

227. Which of the following capacitors can be used for temperature compensation ?

A)Paper capacitor
B)Air capacitor
C)None of these answers
D)Ceramic capacitor

228. The value of E within the field due to a point charge can be found with the help of

A)Faraday’s laws
B)Kirchhoff’s laws
C)Coulomb’s laws
D)none of these answers

229. When a capacitor undergoes a dielectric breakdown

A)permanent conduction path is established between plates
B)electrons get scattered
C)electrons cease to move from one plate to another
D)dielectric stores energy rendering plates chargeless

230. As per Coulomb’s law

A)F = Q1 Q2 / ε0 εr d2
B)F = Q1 Q2 / 4 π d2
C)F = Q1 Q2 / 4 π ε0 εr d2
D)F = Q1 Q2 / 4 π ε0 εr d

231. If three capacitors C1, C2 and C3 of values of 1 μF, 2 μF, and 4 μF respectively are in series and connected across a potential of 230V, then charge on each capacitor is

A)131 x 10-6 C
B)161 x 10-6 C
C)121 x 10-6 C
D)111 x 10-6 C

232. If a 6 iF capacitor is charged to 200 V, the charge in coulombs will be

A)900 μC
B)800 μC
C)1600 μC
D)1200 μC

233. An electrolytic capacitor can be used for

A)none of these answers
B)A.C. only
C)both D.C. as well as AC.
D)D.C. only

234. A gang condenser is a

A)polarised capacitor
B)none of these answers
C)ceramic capacitor
D)variable capacitor

235. With steady D.C. voltage from a battery applied to a capacitance, after it charges to the battery voltage, the current in the circuit

A)depends on the current rating of the battery
B)is smaller for larger values of capacitance
C)is greater for larger values of capacitance
D)is zero for any capacitance value

236. The relative permittivity of free space is given by

A)1000
B)100
C)10
D)1

237. For removing static charge from machinery the

A)insulated cabins are constructed
B)any of these answers
C)framework is earthed.
D)machinery is insulated.

238. Equal charges are given to two spheres of different radii. The potential will

A)Be equal on both the sphere
B)None of these answers
C)Be more on the bigger sphere
D)Be more on the smaller sphere

239. A region around a stationary electric charge lias

A)an electric field
B)both an electric field and a magnetic field
C)none of these answers
D)a magnetic field

240. A capacitor consists of two

A)conductors separated by an insulator
B)ceramic plates and one mica disc
C)insulators separated by a dielectric
D)silver-coated insulators

241. For a good 0.05 μF capacitor ohmmeter reading should

A)show high resistance momentarily and then a very low resistance
B)not move at all
C)show low resistance momentarily and back off to a very high resistance
D)go quickly to 50 ohm approximately and remain there

242. Two copper spheres A (hollow) and B (solid) are of same diameter and are charged to the same potential.

A)None of the sphere will hold any charge.
B)A will hold more charge in comparison to that of B.
C)A will hold less charge in comparison to that of B.
D)Both of the spheres will hold the same charge

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