Electricity Fundamentals 1000+ MCQ with answer for RRB Group D

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

2. If the magnetic material is located within a coil through which alternating current (60 Hz frequency) flowsa then __________ hysteresis loops will be formed
A.
B.
C.
D.
Answer : A

3. The B-H curve of ________ is not a straight line.
A. air
B. wood
C. silicon steel
D. soft iron
Answer : D

4. 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

5. 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

6. The relative permeability of a magnetic material is 10^5. What is its permeability?
A. 4 × 10^5 H/m
B. 4 × 10^-12 H/m
C. 4× 10^-2 H/m
D. 4 × 10^7H/m
Answer : C

7. 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

8. 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

9. 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

10. Paramagnetic substance has a relative permeability of
A. Slightly less than one
B. Equal to one
C. Slightly equal to one
D. Very much greater than one
Answer : C

11. 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

12. The electric field intensity between the parallel plate air capacitor is 20 N/C. If an insulating slab of relative permittivity 5 is placed between the platesa then electric field intensity will be
A. 20 N/C
B. 100 N/C
C. 4N/C
D. 40 N/C
Answer : C

13. 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

14. Defined as the ratio of the volume occupied by the atoms or ions in a unit cell divided by the volume of the unit cell and is used to measure the compactness of a crystal.
A. Atomic packing factor (APF)
B. Ionic Packing Ratio (IPR)
C. Atomic compacting factor (ACF)
D. Ionic compacting ratio (ICR)
Answer : A

15. What is the measure of the density and sign of the electric charge at a point relative to that at some time?
A. Electric potential
B. Electric charge
C. Electric current
D. Electric intensity
Answer : A

16. If the number of valence electrons of an atom is less than 4a the substance is called
A. a conductor
B. a semiconductor
C. an insulator
D. a superconductor
Answer : A

17. 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

18. 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

19. The ability of a mechanically stressed ferromagnetic wire to recognize rapid switching of magnetization when subjected to a dc magnetic field.
A. Wartheim effect
B. Wiedemann effect
C. Wiegand effect
D. Edison effect
Answer : C

20. A group of magnetically aligned atoms is called
A. Range
B. Lattice
C. Domain
D. Crystal
Answer : C

21. The direction of force o a current carrying conductor placed in a m found by
A. Cork screw rule
B. Fleming's left hand rule
C. Fleming's right hand rule
D. using a compass
Answer : B

22. What is the SI unit of reluctance?
A. At
B. At/m
C. N/Wb
D. At/Wb
Answer : D

23. The process by which an emf and hence current is generated or induced in a conductor when there is a change in the magnetic flux linking the conductor is called
A. Electromagnetic induction
B. Mutual induction
C. Faraday's law
D. Electromagnetic interference
Answer : A

24. Which of the following electric quantities is vector in character?
A. Field
B. Charge
C. Energy
D. Potential Difference
Answer : A

25. A germanium atom has an atomic weight of72. How many neutrons are there?
A.
B.
C.
D.
Answer : B

26. Electronic current in a wire is the flow of ____________ electrons.
A. free
B. valence
C. bound
D. loose
Answer : A

27. If the relative permittivity of a material is 10a then its permittivity is
A. 4 × 10^7F/m
B. 4 × 10^-6 F/m
C. 8.854× 10^-11 F/m
D. 8.854 × 10^-12 F/m
Answer : C

28. If the number of valence electrons of an atom is exactly 4a then the substance is called
A. a semiconductor
B. a conductor
C. an insulator
D. a cryogenic conductor
Answer : A

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

30. 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

31. The tiniest element of matter
A. Atom
B. Proton
C. Electron
D. Neutron
Answer : A

32. 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

33. If the value of 25 of a conductor is 1/230 per oCa then the value of 0is
A. 1/180 peroC
B. 1/150 per oC
C. 1/280 per oC
D. 1/230 per oC
Answer : A

34. The force of attraction or repulsion between two magnetic poles is directly proportional to their strengths.
A. Newton's first law
B. Faraday's first law of electromagnetic induction
C. Coulomb's first law
D. Coulomb's second law
Answer : C

35. Theory of ferromagnetic phenomena which assumes each atom is a permanent magnet which can turn freely about its center under the influence of applied field and other magnets.
A. Ewing's theory of ferromagnetism
B. Oersted's ferromagnetism theory
C. Maxwell's magnetic theory
D. Ampere's circuital law
Answer : A

36. 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

37. Define as that pole which when placed in air from a similar and equal pole repels it with a force of newtons
A. North pole
B. South pole
C. Unit pole
D. Magnetic pole
Answer : C

38. 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

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

40. Under ordinary conditionsa a body is considered
A. positively charged
B. neutral
C. negatively charged
D. stable
Answer : B

41. The net electrical charge in an isolated system remains constant. This is known as
A. Law of conservation of charge
B. Coulomb's first law
C. Coulomb's second law
D. Law of conservation of energy
Answer : A

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

43. The contribution to the ionization in an ionization chamber by electrons liberated from t he walls.
A. Skin effect
B. Walt effect
C. Hall effect
D. Edison effect
Answer : B

44. Flux density is measured in
A. Tesia
B. Weber
C. Ampere- turn
D. Maxwell
Answer : A

45. Which of the following has the least number of valence electrons?
A. Conductor
B. Semiconductor
C. Insulator
D. Semi- insulator
Answer : A

46. 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

47. The simplest type of atom to exist is the ______ atom.
A. Helium
B. Hydrogen
C. Boron
D. Oxygen
Answer : B

48. 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

49. A magnetic material losses its ferromagnetic properties at a point called
A. Curie temperature
B. Inferred absolute temperature
C. Room temperature
D. Absolute temperature
Answer : A

50. What is the diameter of an atom?
A. About 10^-10 m
B. About 10^-10 cm
C. About 10^-10 mm
D. About 10^-10 �m
Answer : A