1000+ Electricity Fundamentals MCQ for SSC Stenographer [Solved]

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

2. 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

3. Defined as the number of lines per unit area through any substance in a plane at right angles to the lines of force
A. Flux
B. Flux lines
C. Flux density
D. Flux intensity
Answer : C

4. 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

5. 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

6. When a wire loop is rotated in a magnetic field the direction of the induced emf changes one in every _______ revolution
A.
B.
C.
D.
Answer : B

7. Magnetic intensity is a
A. Phasor quantity
B. Physical quantity
C. Scalar quantity
D. Vector quantity
Answer : D

8. The flux density in an air-cored coil is 10^-3 Wb/m^2. With a cast iron core of relative permeability 100 inserteda the flux density will become
A. 10^-3 Wb/m^2
B. 10^-2 Wb/m^2
C. 10^3 Wb/m^2
D. 0.1 Wb/m^2
Answer : D

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

10. 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

11. 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

12. The phenomenon by which a magnetic substance becomes a magnet when it is place near a magnet
A. Magnetic effect
B. Magnetic phenomenon
C. Magnetic induction
D. Electromagnetic induction
Answer : C

13. A magnetic pole produces 5000 field lines. How much is the flux in webers? A. 50 × 10^-6
A. 5 × 10^-6
B. 500 × 10^-6
C. 500 × 10^-5
D.
Answer : A

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

15. What is the relative permittivity of air?
A.
B.
C. 8.854 × 10^-12
D. 4 × 10^7
Answer : B

16. Permanent magnets can be found in
A. electric bells
B. earphones
C. relays
D. dy namic loudspeakers
Answer : B

17. 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

18. The induced emf in a wire loop that is moved parallel to a uniform magnetic field is
A. Zero
B. Dependent on the area of the loop
C. Dependent on the shape of the loop
D. Dependent on the magnitude of the field
Answer : A

19. 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

20. What solid has no defined crystal structure except perhaps in the arrangement of the nearest neighboring atoms or ions?
A. Crystalline
B. Amorphous
C. Polycrystalline
D. Poly amorphous
Answer : B

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

22. One of the solid structures in which the position of the atoms or ions are predetermined
A. Crystalline solid
B. Amorphous solid
C. Polycrystalline solid
D. Poly amorphous solid
Answer : A

23. The branch of Engineering which deals with the magnetic effect of electric current is known as
A. Magnetism
B. Electromagnetism
C. Electrical engineering
D. Electronics engineering
Answer : B

24. Electric field intensity is measured in
A. volts/meter
B. Newton/meter
C. Newton-meter
D. Amperes/meter
Answer : A

25. 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

26. 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

27. How many electrons are needed in the valence orbit to give a material's stability?
A.
B.
C.
D.
Answer : A

28. 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

29. The ability of a material to conduct magnetic flux through it.
A. Permittivity
B. Reluctivity
C. Conductivity
D. Permeability
Answer : D

30. When the relative permeability of a material is much greater than 1a it is called _______ material.
A. diamagnetic
B. ferromagnetic
C. paramagnetic
D. non-magnetic
Answer : B

31. 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

32. 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

33. The reluctance of the magnetic circuit is ________ relative permeability of the material comprising the circuit.
A. directly proportional to
B. inversely proportional to
C. independent of
D. dependent of
Answer : B

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

35. 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

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

37. The phenomenon by which a subtracts pieces of iron
A. Magnetism
B. Electromagnetism
C. Naturalism
D. Materialism
Answer : A

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

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

40. If the number of valence electrons of an atom is more than 4a the substance is called
A. a semiconductor
B. a conductor
C. an insulator
D. a semi-insulator
Answer : C

41. The emf induced in a coil due to the change of its own flux linked with it is called
A. Mutually induced emf
B. Dynamically induced emf
C. Statically induced emf
D. Self induced emf
Answer : D

42. 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

43. The current of electric circuit is analogous to which quantity of a m
A. Mmf
B. Flux
C. Flux density
D. R eluctivity
Answer : B

44. 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

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

46. 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

47. Electromotive force in a circuit
A. causes free electrons to flow
B. increases the circuit resistance
C. maintains circuit resistance
D. is needed to make the circuit complete
Answer : A

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

49. 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

50. Which of the following materials has the highest dielectric strength?
A. Glass
B. Oiled paper
C. Mica
D. Air
Answer : A