RRB NTPC - Electricity Fundamentals 1000+ MCQ [Solved] PDF Download

1. What is the unit of reluctance?
A. Maxwell
B. Gauss
C. At/Wb
D. Weber
Answer : C

2. What is the relative permittivity of air?
A.
B.
C. 8.854 × 10^-12
D. 4 × 10^7
Answer : B

3. A magnetizing force of 1000 AT/m will produce a flux density of __________ i
A. 1.257 mWb/m^2
B. 0.63 Wb/m^2
C. 1.257 Wb/m^2
D. 0.63 mWb/m^2
Answer : A

4. The K shell or the first shell has how many permissible number of orbiting electrons?
A.
B.
C.
D.
Answer : B

5. What determines the atomic number of an element?
A. The number of protons
B. The number of electrons
C. The number of neutrons
D. The number of neutrons and protons
Answer : A

6. Residual magnetism refers to the flux densitya which exists in the iron core when the magnetic field intensity is
A. Minimized
B. Reduced to zero
C. Maximize
D. Unity
Answer : B

7. The physical motion resulting from the forces of magnetic fields is called
A. Motor action
B. Rotation
C. Repulsion
D. Torque action
Answer : A

8. The permeability of a material having a flux density of 5 Wb/m^2 is 10^-5 H/m. What is the value of magnetizing force?
A. 5 × 10^-5 N/Wb
B. 500 × 10^3 N/Wb
C. 4 × 10^7N/Wb
D. 4 × 10^7N/Wb
Answer : B

9. An alloy of 40 percent iron and 60 percent nickel.
A. Alnico
B. Permalloy
C. Hipernik
D. Manganin
Answer : C

10. Who developed the electromagnetic theory of light in 1862?
A. Heinrich Rudolf Hertz
B. Wilhelm Rontgen
C. James Clerk Maxwell
D. Andre Ampere
Answer : C

11. Whenever a conductor cuts magnetic fluxa an emf is induced in it. This is known as
A. Coulomb's law
B. Joule's law
C. Faraday's law
D. Ohm's law
Answer : C

12. The force of attraction or repulsion between two magnetic poles is inversely proportional to the square of the distance between them. This is known as
A. Newton's first law
B. Faraday's first law of electromagnetic induction
C. Coulomb's first law
D. Coulomb's second law
Answer : D

13. Electric potential is a _______ quantity.
A. scalar
B. phasor
C. vector
D. variable
Answer : A

14. One farad equals
A. 1 coulomb/volt
B. 1 newton/coulomb
C. 1 newton-meter
D. 1 volt/second/ampere
Answer : A

15. The magnitude of the induced emf in a coil is directly proportional to the rate of change of flux linkages. This is known as
A. Joule's Law
B. Faraday's second law of electromagnetic induction
C. Faraday's first law of electromagnetic induction
D. Coulomb's Law
Answer : B

16. Ohm's law can be used only to a _____ circuit or component.
A. Unilateral
B. Exponential
C. Trivalent
D. Linear
Answer : D

17. The force between two magnetic poles varies with the distance between them. The variation is ______ to the square of that distance.
A. Equal
B. Greater than
C. Directly proportional
D. Inversely proportional
Answer : D

18. Electric field intensity is measured in
A. volts/meter
B. Newton/meter
C. Newton-meter
D. Amperes/meter
Answer : A

19. The current of electric circuit is analogous to which quantity of a m
A. Mmf
B. Flux
C. Flux density
D. R eluctivity
Answer : B

20. The force between two charges placed a given distance apart ______ as the relative permittivity of the medium is increased.
A. increases
B. decreases
C. remains unchanged
D. becomes infinite
Answer : B

21. Referred to as the specific reluctance of a material
A. Resistivity
B. Reluctivity
C. Conductivity
D. Permeability
Answer : B

22. If the value of 0 a conductor is 1/234 per oCa then the value of 18is
A. 1/218 per oC
B. 1/252 peroC
C. 1/272 per oC
D. 1/273 per oC
Answer : B

23. The emf induced in a coil due to the change of its own flux linked with it is called
A. Mutually induced emf
B. Dynamically induced emf
C. Statically induced emf
D. Self induced emf
Answer : D

24. The conduction of electricity across the surface of a dielectric is called
A. creepage
B. skin effect
C. surface effect
D. crosstalk
Answer : A

25. A law establishing the fact that the algebraic su of the rises and drops of the mmf around a closed loop of a magnetic circuit is equal to zero.
A. Kirchhoff's circuital law
B. Maxwell's circuital law
C. Ampere's circuital law
D. Coulomb's circuital law
Answer : C

26. The ability of a material to conduct magnetic flux through it.
A. Permittivity
B. Reluctivity
C. Conductivity
D. Permeability
Answer : D

27. The uncharged particles which have no effect on its atomic charge.
A. Nucleons
B. Electrons
C. Protons
D. Neutrons
Answer : D

28. What is another name for relative permittivity?
A. Dielectric strength
B. Electric intensity
C. Potential gradient
D. Dielectric constant
Answer : D

29. A law that states that the polarity of the induced voltage will oppose the change in magnetic flux causing the induction.
A. Joule's law
B. Faraday's law
C. Coulomb's law
D. Lenz' law
Answer : D

30. An alloy of 22 percent iron and 78 per cent nickel.
A. Permalloy
B. Alnico
C. Constantan
D. M anganin
Answer : A

31. If on looking at any one end of a solenoid; the direction of current flow is found to be clockwise then the end under observation is a south pole. This is known as
A. Right hand rule
B. Left hand rule
C. Cork screw rule
D. End Rule
Answer : D

32. The quantity of magnetism retained by a magnetic material after withdrawal of the magnetizing force is called
A. Leftover magnetism
B. Hysteresis
C. Residual magnetism
D. Coercivity
Answer : C

33. A permanent magnet does not exert a force on
A. an unmagnetized iron bar
B. a magnetized iron bar
C. a moving electric charge
D. a stationary electric charge
Answer : D

34. How much is the flux in Weber in the above problem?
A. 2 x 10^-5
B. 2 x 10^-3
C. 2 x 10^5
D. 2 x 10^3
Answer : A

35. The unit of flux is _____ in cgs system.
A. Tesia
B. Gilbert
C. Maxwell
D. Oersted
Answer : C

36. Which of the following is used by temporary magnets as the magnetic material?
A. Hardened steel
B. Cobalt steel
C. Soft iron
D. Tungsten steel
Answer : C

37. The force between two magnetic poles is _____ their poles strength.
A. equal to
B. directly proportional to
C. inversely proportional to
D. directly proportional to the square root of
Answer : B

38. A 6- V battery is connected across a solenoid of 100 turns having a resistance of 2 ?a Calculate the number of ampere turns?
A.
B.
C.
D.
Answer : C

39. What is the SI unit of conductance?
A. Siemens
B. Mhos
C. Ohms
D. 1/Ohms
Answer : A

40. If the resistance of a material 2 m long and 2 m^2 in area of cross-section is 1.6 ×10^-8 ?a then its resistivity is
A. 3.2 × 10^-8 ?-m
B. 1.6 × 10^-8 ?-m
C. 0.64 × 10^-8 ?-m
D. 0.16 × 10^-8 ?-m
Answer : B

41. The temperature coefficient of resistance of eureka is
A. p ositive
B. negative
C. almost zero
D. i nfinite
Answer : C

42. What is the SI unit of specific resistance or resistivity?
A. Ohm-circular mil per inch
B. Ohm-circular mil per foot
C. Ohm-m
D. Ohm-cm
Answer : C

43. The magnetic flux through a wire loop in a magnetic field does not d
A. T he area of the loop
B. The magnitude of the field
C. The shape of the loop
D. The angle between the plane of the loop and the direction
Answer : C

44. A theorem which states that an electric current flowing in a circuit produces a magnetic field at external points equivalent to that due to a magnetic shell whose bounding edge is the conductor and whose strength of the current.
A. Joule's law
B. Faraday's law
C. Volta's theorem
D. Ampere's theorem
Answer : D

45. Germanium atom has ______ protons and ______ electrons.
A. 32, 32
B. 32, 42
C. 42, 32
D. 34, 34
Answer : A

46. Electromotive force in a circuit
A. causes free electrons to flow
B. increases the circuit resistance
C. maintains circuit resistance
D. is needed to make the circuit complete
Answer : A

47. If a magnetic flux cuts across 200 turns at a rate of 2Wb/sa the induced voltage according to Faraday's law is about
A. 400 V
B. 100 V
C. 200 V
D. 600 V
Answer : A

48. One ampere- turn is equivalent to _____ gilberts
A.
B.
C.
D.
Answer : B

49. What is the value of the absolute permittivity of air?
A. 8.854 F/m
B. 8.854 × 10^-12 mF/m
C. 8.854× 10^-12 F/m
D. 8.854 × 10^-12 F/m
Answer : C

50. Back emf refers to the
A. Current equal to the applied emf
B. Opposing emf
C. Current opposing the applied emf
D. Voltage opposing the applied emf
Answer : D