Electricity Fundamentals MCQ Solved Paper for RBI Grade B officer

1. Magnetic effects of the earth as a huge magnet with north and south poles.
A. Diamagnetic
B. Ferromagnetic
C. Terrestrial magnetism
D. Terrestrial ferromagnetism
Answer : C

2. 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

3. Materials that have very high permeabilities (hundreds and even thousands times of that of free space)
A. Paramagnetic
B. Non- magnetic
C. Ferromagnetic
D. Diamagnetic
Answer : C

4. 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

5. 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

6. A principle that states that only two electrons with different spins are allowed to exist in a given orbit
A. Bohr's principle
B. Pauli exclusion principle
C. Avogadro's principle
D. Coulomb's principle
Answer : B

7. The magnetic potential in a magnetic circuit can be measured in terms of
A. Mmf
B. Emf
C. Farad
D. Coulomb
Answer : A

8. Materials whose permeabilities are slightly greater than that of free space
A. Paramagnetic
B. Non- magnetic
C. Ferromagnetic
D. Diamagnetic
Answer : A

9. A 200-watt lamp working for 24 hours will consume approximately _____ units.
A.
B.
C.
D.
Answer : B

10. 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

11. 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

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

13. 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

14. Which of the following magnetic materials can be easily magnetized in both direction?
A. Soft magnetic materials
B. Hard magnetic materials
C. High hysteresis loss materials
D. Low hysteresis loss materials
Answer : A

15. The magnetic field of a bar magnet most closely resembles the magnetic field of
A. a horseshoe magnet
B. a straight current- carrying wire
C. a stream of electrons moving parallel to one another
D. a current- carrying wire loop
Answer : D

16. 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

17. 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

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

19. 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

20. Calculate the permeability (in T/A. t/m) of a magnetic material that has a relative permeability of 300
A. 3.78 x 10^4
B. 3.78 x 10^-5
C. 3.78 x 10^-3
D. 3.78 x 10^-6
Answer : A

21. 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

22. What is used as the insulating material or dielectric in an electric ion
A. Oiled paper
B. Mica
C. Paraffin
D. Tit anate compound
Answer : B

23. If two similar charges 1 coulomb each are placed 1 m apart in aira then the force of repulsion is
A. 8 × 10^6 N
B. 9 × 10 ^9 N
C. 10^6 N
D. 5 × 10^6 N
Answer : B

24. The emission of electrons from hot bodies is called
A. Radiation effect
B. Edison effect
C. Skin effect
D. Half effect
Answer : B

25. 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

26. What bond is formed when one or more electrons in the outermost energy orbit of an atom are transferred to another?
A. Ionic
B. Covalent
C. Metallic
D. Van der Waals
Answer : A

27. 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

28. 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

29. The property of magnetic materials of retaining magnetism after withdrawal of the magnetizing force is known as
A. Retentivity
B. Reluctivity
C. Resistivity
D. Conductivity
Answer : A

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

31. What type of bond is formed when there exists some form of collective interactions between the (negatively charged) electrons and (positively charged) nuclei in a solid?
A. Ionic
B. Covalent
C. Metallic
D. Van der Waals
Answer : C

32. If a 20 V potential is applied across a relay coil with 50 turns having 1 ? of resistancea the total magnetomotive producing magnetic flux in the circuit is
A. 10 Wb
B. 50 T
C. 1000 A t/m
D. 1000,t
Answer : D

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

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

35. What is used as the dielectric material in high voltage transformers?
A. Mica
B. Paraffin
C. Porcelain
D. Oiled paper
Answer : C

36. 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

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

38. Used to maintain strength of magnetic field
A. Container
B. Air gap
C. Keeper
D. S ource
Answer : C

39. A one cubic cm of copper has how many free electrons at room temperature?
A. 80 × 10^18
B. 8.5 × 10^22
C. 20 × 10^10
D. 50 × 10^20
Answer : B

40. 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

41. Whenever a flux inking a coil or current changesa an emf is induced in it. This is known as
A. Joule's Law
B. Coulomb's Law
C. Faraday's first law of electromagnetic induction
D. Faraday's second law of electromagnetic induction
Answer : C

42. Small voltages generated by a conductor with current in an external magnetic field.
A. Skin effect
B. Magnetic effect
C. Hall effect
D. Flywheel Effect
Answer : C

43. 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

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

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

46. 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

47. 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

48. 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

49. What principle states that each electron in an atom must have a different set of quantum numbers?
A. Inclusion principle
B. Exclusion principle
C. Quantum principle
D. Electron principle
Answer : B

50. 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