Railways NTPC (Technical Ability) Electric Circuits and Field Question Bank

done Electric Circuits and Field Total Questions - 50

• question_answer1)
  Coulomb's law is true for
  A)
   atomic distances \[(={{10}^{-11}}m)\] done clear
  B)
   nuclear distances \[(={{10}^{-15}}m)\] done clear
  C)
   charged as well as uncharged particles done clear
  D)
   all the distances done clear
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• question_answer2)
  Electric flux at a point in an electric field is
  A)
   positive             done clear
  B)
   negative done clear
  C)
   zero                              done clear
  D)
   none of these done clear
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• question_answer3)
  As the temperature of a conductor increases, its resistivity and conductivity change. The ratio of resistivity to conductivity
  A)
   increases                       done clear
  B)
   decreases          done clear
  C)
   remains constant            done clear
  D)
   may increase or decrease depending on the actual temperature. done clear
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• question_answer4)
  The unit of capacitance of a capacitor is
  A)
   joule                             done clear
  B)
   henry done clear
  C)
   farad                            done clear
  D)
   ampere done clear
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• question_answer5)
  Consider the following two statements. [A] Kirchoff's junction law follows from conservation of charge. [B] Kirchoff's loop law follows from conservative nature of electric field.
  A)
   Both A and B are correct done clear
  B)
   A is correct but B is wrong done clear
  C)
   B is correct but A is wrong done clear
  D)
   Both A and B are wrong done clear
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• question_answer6)
  The unit of specific resistance is
  A)
   \[\Omega \,{{m}^{-1}}\]                      done clear
  B)
   \[\Omega \,{{m}^{-1}}\] done clear
  C)
   \[\Omega \,m\]                          done clear
  D)
   \[2.5\,\Omega \,m\] done clear
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• question_answer7)
  The example of non-ohmic resistance is
  A)
   diode                done clear
  B)
   copper wire done clear
  C)
   filament lamp                done clear
  D)
   carbon resistor done clear
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• question_answer8)
  Kirchoff's first law, Le., S i = 0 at a junction, deals with the conservation of
  A)
   charge              done clear
  B)
   energy done clear
  C)
   momentum                   done clear
  D)
   angular momentum done clear
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• question_answer9)
  One Kilowatt hour is equal to
  A)
   \[36\times {{10}^{5}}\,joule\]   done clear
  B)
   \[36\times {{10}^{3}}\,joule\] done clear
  C)
   \[{{10}^{3}}\,joule\]                done clear
  D)
   \[{{10}^{5}}\,joule\] done clear
  View Solution play_arrow

• question_answer10)
  The capacitance between points P and Q in circuit shown in fig is                     
  A)
   \[1\mu F\]                     done clear
  B)
  \[1.5\mu F\]  done clear
  C)
   \[9\mu F\]                     done clear
  D)
   \[6.75\mu F\]  done clear
  View Solution play_arrow

• question_answer11)
     Specific resistance of a conductor depends upon:
  A)
   composition of the conductor done clear
  B)
   length of the conductor done clear
  C)
   area of cross-section of the conductor done clear
  D)
   resistance of the conductor done clear
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• question_answer12)
  With increase in temperature, the resistance of copper:
  A)
   decreases                      done clear
  B)
   increases done clear
  C)
   becomes zero                 done clear
  D)
   remains constant done clear
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• question_answer13)
  Specific resistance of a substance is measured in:
  A)
   ohm/m             done clear
  B)
   m/ohm done clear
  C)
   mho/m             done clear
  D)
   mho done clear
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• question_answer14)
  One Kilowatt hour of electrical energy is the same as
  A)
   \[36\times 105\,\,Watts\] done clear
  B)
   \[36\times 105\,\,ergs\] done clear
  C)
   \[36\times 105\,\,Joules\] done clear
  D)
   \[36\times 105\,\,B.T.V\] done clear
  View Solution play_arrow

• question_answer15)
  Krichoffs current laws is applicable to only:
  A)
   closed loops in a network done clear
  B)
   electronic circuits done clear
  C)
   junctions in a network done clear
  D)
   electric circuits done clear
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• question_answer16)
  Filaments of electric bulbs are usually made of:
  A)
   nichrome                      done clear
  B)
   carbon done clear
  C)
   tungsten                        done clear
  D)
   copper done clear
  View Solution play_arrow

• question_answer17)
  Ohm's law is not applicable to:
  A)
   D. c. circuits                  done clear
  B)
   High currents done clear
  C)
   Small resistors   done clear
  D)
   Semiconductors done clear
  View Solution play_arrow

• question_answer18)
  The element of electric heater is made of:
  A)
   copper              done clear
  B)
   carbon done clear
  C)
   steel                             done clear
  D)
   nichrome done clear
  View Solution play_arrow

• question_answer19)
  In the SI system of units, the unit of force is:
  A)
   kg wt                done clear
  B)
   newton done clear
  C)
   joule                             done clear
  D)
   N-m done clear
  View Solution play_arrow

• question_answer20)
  A light dependent resistors is basically a:
  A)
   power resistor    done clear
  B)
   non-metallic resistor done clear
  C)
   carbon resistor   done clear
  D)
   variable resistor done clear
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• question_answer21)
  In MKS system one Kilowatt is equal to
  A)
   1.36 HP                       done clear
  B)
   1.34 HP done clear
  C)
   1.5HP              done clear
  D)
   1.6HP done clear
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• question_answer22)
  Voltage dependent resistors are used as:
  A)
   current stabilizers            done clear
  B)
   as heating elements done clear
  C)
   for inductive circuits       done clear
  D)
   to suppress surges done clear
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• question_answer23)
  In which of the following the resistance decreases with rise in temperature?
  A)
   LDR                             done clear
  B)
   NTC thermistors done clear
  C)
   Nichrome conductors      done clear
  D)
   ACSR conductors done clear
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• question_answer24)
  An uncharged metal ball is placed in the uniform electric field of a plane capacitor. Which of them correctly represents the field lines on the ball?
  A)
     done clear
  B)
    done clear
  C)
    done clear
  D)
   None of the above done clear
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• question_answer25)
  There is a point charge +q inside a hollow sphere and a point charge -q just outside its surface. The total flux passing through the sphere
  A)
   \[\frac{-q}{{{\in }_{0}}}\]                                 done clear
  B)
   \[\frac{q}{{{\in }_{0}}}\] done clear
  C)
   \[\frac{2q}{{{\in }_{0}}}\]                                done clear
  D)
   zero.     done clear
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• question_answer26)
  Figures below show regular hexagons, with charges at the vertices, hi which of the following cases the electric field at the centre is not zero. (1)        (2) (3)         (4)
  A)
   1                                 done clear
  B)
   2 done clear
  C)
   3                                 done clear
  D)
   4 done clear
  View Solution play_arrow

• question_answer27)
  For a given surface the Gauss's law is stated as \[\oint{\overrightarrow{E}}.d\overrightarrow{A}=0\] From this we can conclude that
  A)
   E is necessarily zero on the surface done clear
  B)
   E is perpendicular to the surface at every point   done clear
  C)
   The total flux through the surface is zero done clear
  D)
   The flux is only going out of the surface done clear
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• question_answer28)
  The electric field due to a uniformly charged sphere of radius R as a function of the distance from its centre is represented graphically by
  A)
   electric field is zero but potential is not zero done clear
  B)
   electric field is not zero but potential is zero done clear
  C)
   neither electric field nor potential is zero done clear
  D)
   None of these done clear
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• question_answer29)
  Two charges are at a distance d apart. If a copper plate (conducting medium) of thickness \[\frac{d}{2}\]is placed between them, the effective force will be
  A)
   2F                                done clear
  B)
   F/2 done clear
  C)
   0                                 done clear
  D)
   \[\sqrt{2F}\] done clear
  View Solution play_arrow

• question_answer30)
  Electric potential at any point is \[V=-5x+3y+\sqrt{15z},\] then the magnitude of the electric field is
  A)
   \[3\sqrt{2}\]                  done clear
  B)
   \[4\sqrt{2}\] done clear
  C)
   \[5\sqrt{2}\]                  done clear
  D)
   \[7\] done clear
  View Solution play_arrow

• question_answer31)
  The RMS value of the voltage u(t} = 3 + 4cos (3t is
  A)
   \[\sqrt{17}V\]                done clear
  B)
   \[5V\] done clear
  C)
   \[7V\]                           done clear
  D)
   \[(3+2\sqrt{2})\,\,V\] done clear
  View Solution play_arrow

• question_answer32)
  If E is the electric field intensity then \[\Delta .(\Delta \times E)\] is equal to
  A)
   \[E\]                             done clear
  B)
   \[|\overrightarrow{E}|\] done clear
  C)
   null vector                     done clear
  D)
   zero done clear
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• question_answer33)
  A solid sphere made of insulating material has a radius R and has a total charge Q distributed uniformly in its volume. What is the magnitude of the electric field intensity, E, at a distance r (0 < r < R) inside the sphere?
  A)
   \[\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{Qr}{{{R}^{3}}}\]                  done clear
  B)
   \[\frac{3}{4\pi {{\varepsilon }_{0}}}\frac{Qr}{{{R}^{3}}}\] done clear
  C)
   \[\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{Q}{{{r}^{2}}}\]                    done clear
  D)
   \[\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{QR}{{{r}^{3}}}\] done clear
  View Solution play_arrow

• question_answer34)
  The number of chords in the graph of the given circuit will be
  A)
   3                                 done clear
  B)
   4 done clear
  C)
   5                                 done clear
  D)
   6 done clear
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• question_answer35)
  The current through the\[2K\Omega \]resistance in the circuit shown is
  A)
   zero                              done clear
  B)
   1 mA done clear
  C)
   2 mA               done clear
  D)
   6 mA done clear
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• question_answer36)
  Which of the following statements associated with capacitors is wrong?
  A)
   A capacitor resists an abrupt change in the voltage across it in a manner analogous to the way a spring resists abrupt change in the current flowing through it. done clear
  B)
   A capacitor resists an abrupt change in the current flowing through it. done clear
  C)
   It is impossible to change the voltage across capacitor ' by a finite amount in zero time, for this requires infinite current through the capacitor. done clear
  D)
   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. done clear
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• question_answer37)
  To a highly inductive circuit, a small capacitance is added in series. The angle between voltage and current will
  A)
   increase done clear
  B)
   Decrease done clear
  C)
   remain nearly the same done clear
  D)
   become in determinant      done clear
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• question_answer38)
  The resistivity of the conductor depends on
  A)
   Area of the conductor. done clear
  B)
   Length of the conductor. done clear
  C)
   Type of material. done clear
  D)
   None of these. done clear
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• question_answer39)
  A capacitor carries a charge of \[0.1C\,\,at\,\,5\,\,V\]Its capacitance is
  A)
   0.02 F              done clear
  B)
     0.5 F done clear
  C)
   0.05 F              done clear
  D)
     0.2 F done clear
  View Solution play_arrow

• question_answer40)
  1 F is theoretically equal to
  A)
   1 ohm of resistance done clear
  B)
   Ratio of 1 V to 1 C done clear
  C)
   Ratio of 1 C to 1 V done clear
  D)
   None of these done clear
  View Solution play_arrow

• question_answer41)
  Which of the followings is/are active element?
  A)
   Voltage source   done clear
  B)
     Current source done clear
  C)
   Both                            done clear
  D)
     None of these. done clear
  View Solution play_arrow

• question_answer42)
  Power dissipation in ideal inductor is
  A)
   Maximum                     done clear
  B)
   Minimum done clear
  C)
   Zero                             done clear
  D)
   A finite value done clear
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• question_answer43)
  Which of the following are the passive elements?
  A)
   Resistor             done clear
  B)
   Bulb done clear
  C)
   Both                done clear
  D)
   None of these. done clear
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• question_answer44)
  Internal resistance of ideal voltage source is
  A)
   Zero                 done clear
  B)
   Infinite done clear
  C)
   Finite                done clear
  D)
   100 ohms done clear
  View Solution play_arrow

• question_answer45)
  Mesh analysis is applicable for
  A)
   Planar networks done clear
  B)
   Non planar networks done clear
  C)
   Both planar & non-planar networks. done clear
  D)
   Neither planar nor non planar networks done clear
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• question_answer46)
  KCL works on the principle of which of the following
  A)
   Law of conservation of charge done clear
  B)
   Law of conservation of energy done clear
  C)
   Both done clear
  D)
   Nose of the above done clear
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• question_answer47)
  Average power taken by the pure capacitor is
  A)
   Zero                 done clear
  B)
   Minimum done clear
  C)
   Maximum                     done clear
  D)
   Any of the above done clear
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• question_answer48)
  KVL works on the principle of
  A)
   Law of conservation of charge done clear
  B)
   Law of conservation of energy done clear
  C)
   Both done clear
  D)
   None of the above done clear
  View Solution play_arrow

• question_answer49)
  Super position theorem is not applicable for
  A)
   Current calculations done clear
  B)
   Voltage calculations done clear
  C)
   Power calculations done clear
  D)
   None of the above done clear
  View Solution play_arrow

• question_answer50)
  Internal resistance of ideal current source is
  A)
   Zero                             done clear
  B)
   Infinite done clear
  C)
   Finite                done clear
  D)
   100 ohms done clear
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