Electricity Fundamentals 1000+ MCQ with answer for RBI Assistant

1. 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

2. 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

3. The force acting on a unit n- pole placed at that point is called
A. Magnetic field intensity
B. Electric field intensity
C. Electromagnetic field intensity
D. Intensity magnetization
Answer : A

4. 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

5. Who discovereda the relationship between magnetism and electricity that serves as the foundation for the theory of electromagnetism?
A. Luigi Galvani
B. Hans Christian Oersted
C. Andre Ampere
D. Charles Coulomb
Answer : B

6. Temporary magnets are commonly employed in
A. electric instruments
B. motors
C. moving coils loudspeakers
D. magnetos
Answer : B

7. What is the other name for dielectric strength?
A. Breakdown voltage
B. Electric intensity
C. Potential gradient
D. Dielectric constant
Answer : A

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

9. Hydrogen is an example of a _____ material.
A. Paramagnetic
B. Diamagnetic
C. Ferromagnetic
D. N on- magnetic
Answer : B

10. Which of the following has the highest permeability?
A. Soft iron
B. Steel
C. Air
D. Permalloy
Answer : D

11. What is the reluctance of a magnetic path having a length of 2x 10^-3m and crosssectional area of 2.5 x 10^-3 m^2?
A. 6366 A, t/Wb
B. 6000 A, t/Wb
C. 8x10^-3 A, t/Wb
D. 0.8 A, t/Wb
Answer : A

12. Three charges of +5 Ca -6 C and +9 C are placed inside a sphere. What is the total flux passing through the surface of sphere?
A. 8 C
B. 14 C
C. 20 C
D. -6 C
Answer : A

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

14. 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

15. 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

16. The customary energy unit in atomic and nuclear physics is
A. Joule
B. Volt- coulomb
C. electron-volt
D. Walt- second
Answer : C

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

18. What bond is formed when electrons in the outermost energy orbits of the atoms are shared between two or more electrons?
A. Ionic
B. Covalent
C. Metallic
D. Van der Waals
Answer : B

19. 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

20. Electric lines of force leave or enter the charge surface at an angle of
A. 30o
B. 45 o
C. 90o
D. depending upon the angle of launch and entry
Answer : C

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

22. 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

23. A positively charged body has
A. deficit of electrons
B. excess of neutrons
C. excess of electrons
D. deficit of protons
Answer : A

24. The resistivity of a conductor ___________ with an increase in temperature.
A. increases
B. decreases
C. remains the same
D. becomes zero
Answer : A

25. What is the maximum number of electrons that can be accommodated in the last orbit of an atom?
A.
B.
C.
D.
Answer : C

26. Permeability means
A. The conductivity of the material for magnetic lines of force
B. The magnetization test in the material after exciting field has been removed
C. The strength of an electromagnet
D. The strength of the permanent magnet
Answer : A

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

28. What is the main advantage of temporary magnets?
A. The magnetic flux can be changed.
B. Hysteresis can be decreased.
C. Magnetic materials can be used.
D. Abundance of ferromagnetic material that can be temporarily magnetized.
Answer : A

29. 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

30. Who discovered superconductivity in 1911?
A. Kamerlingh Onnes
B. Alex Muller
C. GeoryBednorz
D. Charles Coulomb
Answer : A

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

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. 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

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

35. What revolves about the positive nucleus in a definite orbit?
A. Atom
B. Proton
C. Electron
D. Neutron
Answer : C

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

37. Lenz' law states that the direction of the induced emf and hence current
A. Is determined by the rate of current flux
B. Is found by the right hand rule
C. Is found by the left hand rule
D. Always opposes the cause producing it
Answer : D

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

39. The force between two magnetic poles is _____ the relative permeability of the medium.
A. directly proportional to
B. independent of
C. inversely proportional to
D. equal to
Answer : C

40. 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

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

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

43. 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

44. 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

45. Electron is a Greek word for
A. amber
B. Fire
C. Stone
D. Heat
Answer : A

46. 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

47. Amorphous solid is also called
A. Crystalline
B. Non- crystalline
C. Polycrystalline
D. Homogenous
Answer : B

48. 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

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

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