FCI Recruitment - Electricity Fundamentals 1000+ MCQ [Solved] PDF Download

1. 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

2. 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

3. A substance that attracts pieces iron
A. Conductor
B. Semiconductor
C. Magnet
D. All of the above
Answer : C

4. The space outside the magnet where its pole have a force of attraction or repulsion on a magnetic pole is called
A. Magnetic field
B. Electric field
C. Electromagnetic field
D. Free Space Field
Answer : A

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

6. 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

7. What is the unit of magnetomotive force?
A. Volt
B. Tesla
C. Ampere- turn
D. Weber
Answer : C

8. 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

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

10. Electric field intensity at a point due to a given charge ______ if the relative permittivity of the medium decreases.
A. decreases
B. remains unchanged
C. increases
D. b ecomes zero
Answer : C

11. Lenz's law is the consequence of the law of conservation of
A. Energy
B. Charge
C. Field lines
D. Momentum
Answer : A

12. The unit of electrical energy is
A. Joule
B. Watt- second
C. Kilowatt hour
D. All of these
Answer : D

13. 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

14. What is the cgs unit of magnetomotive force?
A. Gilbert
B. Ampere- turn
C. Maxwell
D. Weber
Answer : A

15. The force between two magnetic poles is _______ their pole strengths.
A. directly proportional to
B. the sum of
C. inversely proportional to
D. the product of
Answer : A

16. Gases whose particles are charged are known as
A. Conductors
B. Insulators
C. Gaseous Conductors
D. Plasma
Answer : D

17. A law relating between the magnetic and electric susceptibilities and the absolute temperatures which is followed b ferromagnetsa antiferromagnetsa non-polar ferroelectricsa antiferroelectrics and some paramagnets.
A. Curie's Law
B. Child's Law
C. CR Law
D. Curie-Weiss Law
Answer : D

18. The core of a magnetic equipment uses a magnetic material with
A. Least permeability
B. Low permeability
C. Moderate permeability
D. High permeability
Answer : D

19. 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

20. The hot resistance of an incandescent lamp is about _______ its cold resistance.
A. 10 times
B. 100 times
C. 5 times
D. 50 times
Answer : A

21. Hysteresis loss can be reduced by one of the following.
A. Increasing mmf of the circuit
B. Using material narrow hysteresis loop
C. Using ferromagnetic core
D. Laminating the magnetic circuit
Answer : B

22. 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

23. How many neutrons does a copper atom have?
A.
B.
C.
D.
Answer : B

24. A factor used to correct for the electrostatic forces of the more distant ions in an ionic solid.
A. Avogadro's number
B. Planck's constant
C. Boltzmann's constant
D. Madelung constant
Answer : D

25. The reluctance of a magnetic circuit varies with
A. length × area
B. area � length
C. length � area
D. length + area
Answer : C

26. Which element has four valence electrons?
A. Conductor
B. Insulator
C. Semiconductor
D. Semi- insulator
Answer : C

27. 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

28. The air space between poles of magnets
A. Air gap
B. Free space
C. Vacuum
D. Atmosphere
Answer : A

29. How many turns are needed to produce a magnetomotive force of 1000 A.t for a coil with 6 amperes?
A. 6000 turns
B. 600 turns
C. 167 turns
D. 67turns
Answer : C

30. Electrons at the outer shell are called
A. Outer shell electrons
B. Inner shell electrons
C. Semiconductor electrons
D. Valence electrons
Answer : D

31. The mass of proton is __________ the mass of an electron.
A. equal to
B. about 1837 times
C. less than
D. 200 tim es
Answer : B

32. The evaporation of electrons from a heated surface is called
A. Radiation
B. Convection
C. Thermionic emission
D. Conduction
Answer : C

33. The ratio of the permeability of material to the permiabiity of air or vacuum.
A. Relative permeability
B. Relative permittivity
C. Relative conductivity
D. Relative reluctivity
Answer : A

34. 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

35. A length of wire has a resistance of 10 ohms. What is the resistance of a wire of the same material three times as long and twice the cross-sectional area?
A. 30 ohms
B. 20 ohms
C. 15 ohms
D. 7 ohms
Answer : C

36. If the length and area of cross-section of a wire are doubleda then its resistance
A. becomes four times
B. becomes sixteen times
C. remains the same
D. becomes two times
Answer : C

37. 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

38. The core of a transformer heats up when its primary is fed from an ac source because of
A. permeability
B. ferromagnetism
C. reluctance of core
D. hysteresis loss
Answer : D

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

40. 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

41. The force which set ups or tends to set up magnetic flux in a magnetic circuit
A. Dynamic force
B. Electromotive force
C. Potential difference
D. Magnetomotive force
Answer : D

42. Which of the following materials has permeability slightly less than that of free space?
A. Paramagnetic
B. Non- magnetic
C. Ferromagnetic
D. Diamagnetic
Answer : C

43. The energy stored in an electrostatic field or electromagnetic field is called
A. Electromagnetic energy
B. Kinetic energy
C. Potential energy
D. R est energy
Answer : C

44. 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

45. One of the common application of an air- cored choke.
A. Radio frequency
B. Audio frequency
C. Power supply
D. Power transformer
Answer : A

46. The magnetic field inside a solenoid
A. is zero
B. is uniform
C. increases with distance from the axis
D. decreases with distance from the axis
Answer : B

47. As the magnetic intensity decreasesa the relative permeability of a magnetic material
A. decreases
B. remains the same
C. increases
D. becomes zero
Answer : C

48. If you hold the conductor with right hand so that the stretched thumb points in the direction of the currenta then encircling fingers will give the direction of magnetic lines of force round the conductor. This is known as
A. Left hand cork screw rule
B. Right hand cork screw rule
C. Left hand rule
D. Right hand rule
Answer : D

49. The resistance of a material is ____________ its area of cross-section.
A. directly proportional
B. independent of
C. inversely proportional to
D. equal to
Answer : C

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