1000+ Electricity Fundamentals Multiple Choice Question Answer [Solved]

1. Defined as a closed path in which magnetic induction or flux flows
A. Electric circuit
B. Magnetic circuit
C. Electronic circuit
D. Electromagnetic circuit
Answer : B

2. The temperature coefficient of resistance of conductors is
A. positive
B. zero
C. negative
D. infinite
Answer : A

3. 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

4. A magnetic flux of 2.5 x10^4 Wb through an area of 5 x10^4 square meters results in
A. 5 Wb
B. 0.5 Tesia of flux density
C. 5x 10^-5 Wb of flux
D. 5000 Tesia of flux density
Answer : B

5. 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

6. An electron- volt (eV) is a unit of
A. Energy
B. Potential difference
C. Charge
D. Momentum
Answer : A

7. One coulomb of charge consists of ________ electrons.
A. 624× 10^16
B. 62.4 × 10^16
C. 6.24 × 10^16
D. 0.624 × 10^16
Answer : A

8. The force acting on a pole of 5 Wb is 25 N. What is the intensity of the magnetic field?
A. 5 N/Wb
B. 25 N/Wb
C. 125 N/Wb
D. 0.2 N/Wb
Answer : A

9. Refers to the non- metallic materials that have the ferromagnetic properties of iron.
A. Ferrites
B. Ferromagnetic
C. Diamagnetic
D. Paramagnetic
Answer : A

10. Bonding of atoms that is due to the force of attraction between positive ions and a group of negative ions
A. Ionic bond
B. Covalent Bond
C. Electrostatic Bond
D. Metallic bond
Answer : D

11. The permittivity of a material is given by one of the following formulas.
A. DE
B. E/D
C. D^2/E
D. D/E
Answer : D

12. Hysteresis is a phenomenon of _________ in a magnetic circuit.
A. setting up constant flux
B. lagging of H behind B
C. lagging B behind H
D. leading B ahead H
Answer : C

13. 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

14. Steel is hard to magnetize because of its
A. Low permeability
B. High permeability
C. High density
D. High retentivity
Answer : A

15. A current if flowing east along a power line. If the earth's field is neglecteda the direction of the magnetic field below it is
A. North
B. South
C. East
D. West
Answer : A

16. Which of the following is used by permanent magnets as the magnetic material?
A. iron
B. nickel
C. soft steel
D. hardened steel
Answer : D

17. 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

18. 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

19. A law stating that the magnetic susceptibilities of most paramagnetic substances are inversely proportional to their absolute temperatures.
A. Curie's Law
B. Child's Law
C. CR Law
D. Curie-Weiss Law
Answer : A

20. What is the SI unit of magnetic flux?
A. Tesla
B. Weber
C. Maxwell
D. Gauss
Answer : B

21. Magnetic field intensity is a ________ quantity.
A. scalar
B. phasor
C. vector
D. variable
Answer : C

22. A law that states that the current in a thermionic diode varies directly with the three- halves power of anode voltage and inversely with the square of the distance between the electrodesa provided operating conditions are such that the current is limited only by the space charge.
A. Hall's law
B. Joule's law
C. Child's law
D. Coulomb's law
Answer : C

23. The relation between absolute permittivity of air ( 0)a absolute p and velocity of light (c) is given by
A. 0 0= c^2
B. 0 0= c
C. 1/ 0 0= c
D. 1/ 0 0= c^2
Answer : D

24. When the current flowsa the magnetic field ��. conductor is in what direction?
A. The same as the current direction
B. Opposite the current direction
C. Omnidirectional
D. In the direction determined by the left hand rule
Answer : D

25. Which of the following is a diamagnetic material?
A. Aluminum
B. Silver
C. Air
D. Cobalt
Answer : C

26. The lagging effect between flux density of the material and the magne
A. Permeance
B. Eddy current
C. Hysteresis
D. R eluctance
Answer : C

27. There are how many compounds available in nature?
A.
B.
C. 300a000
D. Unlimited
Answer : D

28. Permeance of a magnetic circuit is _________ the cross-sectional area of the circuit.
A. directly proportional to
B. inversely proportional to
C. dependent of
D. independent of
Answer : A

29. When the relative permeability of a material is slightly more than 1a it is called ______ material.
A. diamagnetic
B. ferromagnetic
C. paramagnetic
D. non-magnetic
Answer : C

30. A negatively charge body has
A. deficit of electrons
B. excess of protons
C. excess of electrons
D. deficit of neutrons
Answer : C

31. The dielectric constant of most materials lies between
A. 1 and 10
B. 10 and 20
C. 20 and 50
D. 50 and 100
Answer : A

32. If the value of 25 a conductor is 1/255 per oCa then the value of 20is
A. 1/300 per oC
B. 1/250 peroC
C. 1/230 per oC
D. 1/260 per oC
Answer : B

33. Why is it that the magnitude of magnetomotive force required for air gap is much greater than that required for iron part of a magnetic circuit?
A. Because air is a gas
B. Because air has the highest relative permeability
C. Because air is a conductor of magnetic flux
D. Because air has the lowest relative permeability
Answer : D

34. What is the typical saturation flux density for most magnetic materials?
A. 4 Wb/m^2
B. 5 Wb/m^2
C. 1 Wb/m^2
D. 2 Wb/m^2
Answer : D

35. Who discovered that a current-carrying conductor would move when placed in a magnetic field?
A. Michael Faraday
B. Andre Ampere
C. Hans Christian Oersted
D. Gustav Robert Kirchhoff
Answer : A

36. The quantity 10^6 maxwells is equivalent to one
A. Weber
B. Gauss
C. Gilbert
D. Tesla
Answer : A

37. An effect which is generally used in the gausameter to measure flux density.
A. Skin effect
B. Magnetic effect
C. Hall effect
D. Flywheel effect
Answer : C

38. When the relative permeability of a material is slightly less than 1a it is called _____ material.
A. diamagnetic
B. ferromagnetic
C. paramagnetic
D. non-magnetic
Answer : A

39. All matters (gasa liquid and solid) are composed of
A. Neutrons
B. Particles
C. Electrons
D. Atoms
Answer : D

40. It is the reciprocal of reluctance and implies the case of readiness with which magnetic flux is developed.
A. R esistance
B. Conductance
C. Permeance
D. I nductance
Answer : C

41. If the distance between two magnetic poles decreases by 2 timesa the force between them
A. decreases two times
B. increases four times
C. increases two times
D. decreases four times
Answer : B

42. The science of adapting electronics to aerospace flight.
A. Avionics
B. Aerotronics
C. Aerodynamics
D. Astrionics
Answer : D

43. A good conductor has how many valence electrons?
A.
B.
C.
D.
Answer : B

44. Which of the following is a paramagnetic material?
A. Carbon
B. Bismuth
C. Copper
D. Oxygen
Answer : D

45. 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

46. The unit of flux density is
A. Wb/m
B. Tesla
C. At/m
D. N/Wb
Answer : B

47. The electric potential at a point in air due to a charge is 21 V. If the air is replaced by a medium of relative permittivity of 3a then electric potential at that point will be
A. 63 V
B. 21 V
C. 7 V
D. 42 V
Answer : C

48. The reluctance of a magnetic circuit is not dependent on which of the following?
A. Number of turns of coil
B. Magnetomotive force
C. Flux density in the circuit
D. Current in the coil
Answer : C

49. The temperature coefficient of resistance of semiconductors is
A. positive
B. zero
C. negative
D. infinite
Answer : C

50. What is the usual value of leakage coefficient for electrical machines?
A. 0.5 to 1
B. 1 to 5
C. 5 to 10
D. 1.15 to 1.25
Answer : D