1000+ Electricity Fundamentals MCQ for NDA [Solved]

1. 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

2. ______ is an electromagnet with its core in the form of a close magnetic ring.
A. S olenoid
B. Paraboloid
C. Toroid
D. Cycloid
Answer : C

3. 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

4. The magnetic field of a magnetized iron bar when strongly heated
A. Becomes weaker
B. Becomes stronger
C. Reverses in direction
D. is unchanged
Answer : A

5. When the relative permeability of a material is slightly less than 1a it is called _____ material.
A. diamagnetic
B. ferromagnetic
C. paramagnetic
D. non-magnetic
Answer : A

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

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

8. 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

9. Which of the following is used by permanent magnets as the magnetic material?
A. iron
B. nickel
C. soft steel
D. hardened steel
Answer : D

10. 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

11. 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

12. The potential at a point due to a charge is 15 V. If the distance is times, the potential at the point will be
A. 5 V
B. 18 V
C. 45 V
D. 15 V
Answer : A

13. 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

14. Which of the following is a natural magnet?
A. Steel
B. Magnesia
C. Lodestone
D. S oft iron
Answer : C

15. 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

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

17. 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

18. The force of attraction or repulsion between two magnetic poles is inversely proportional to the square of the distance between them. This is known as
A. Newton's first law
B. Faraday's first law of electromagnetic induction
C. Coulomb's first law
D. Coulomb's second law
Answer : D

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

20. The physical motion resulting from the forces of magnetic fields is called
A. Motor action
B. Rotation
C. Repulsion
D. Torque action
Answer : A

21. One weber of flux is equal to _______ magnetic lines of force.
A. 10^6
B. 10^10
C. 4 × 10^7
D. 10^8
Answer : D

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

23. Two similar polesa each 1Wba placed 1 m apart in air will experience a repulsive force of
A. 63000 N
B. 63 × 10^-3 N
C. 8 × 10^12 N
D. 796 kN
Answer : A

24. If the right handed bottle-opener cork screw is assumed to be along the conductor so as to advance in the direction of current flow, the motion of its handle will indicate the direction of magnetic flux produced around the conductor. This is known as
A. Right hand rule
B. Left hand rule
C. Cork screw rule
D. End rule
Answer : C

25. Germanium atom has ______ protons and ______ electrons.
A. 32, 32
B. 32, 42
C. 42, 32
D. 34, 34
Answer : A

26. A law that states that the current in a thermionic diode varies directly with the three- halves power of anode voltage and inversely with the square of the distance between the electrodesa provided operating conditions are such that the current is limited only by the space charge.
A. Hall's law
B. Joule's law
C. Child's law
D. Coulomb's law
Answer : C

27. 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

28. 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

29. Calculate the flux density that will be produced by the field intensity of 2000 a. t/m for a permeability of 126 x 10^-6 T/A.t/m
A. 0.252 G
B. 0.252 x 10^-2 T
C. 0.252 T
D. 0.252 x 10^-2 G
Answer : C

30. Mmf in a magnetic circuit corresponds to _____ in an electric circuit
A. Emf
B. Voltage drop
C. Electric Field Intensity
D. Potential gradient
Answer : A

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

32. Another term for corona discharge.
A. Lightning
B. Sparking
C. Aurora
D. Corona Effect
Answer : C

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

34. 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

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. How is mutual inductance between two coils decreased?
A. By using a common core
B. By moving the coils closer
C. By moving the coils apart
D. By increasing the number of turns of either coil
Answer : C

37. If the value of 0 a conductor is 1/234 per oCa then the value of 18is
A. 1/218 per oC
B. 1/252 peroC
C. 1/272 per oC
D. 1/273 per oC
Answer : B

38. Which of the following is a paramagnetic material?
A. Carbon
B. Copper
C. Bismuth
D. Oxygen
Answer : D

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

40. The electrons in the last orbit of an atom are called _______ electrons.
A. free
B. valence
C. bound
D. thermionic
Answer : B

41. A negative ion results when an atom gains an additional
A. Electron
B. Proton
C. Neutron
D. Atom
Answer : A

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

43. States that the ratio of the thermal conductivity is proportional to the absolute temperature for all metals.
A. Wien's displacement law
B. Hartleys law
C. Hall's law
D. Wiedemann Franz law
Answer : D

44. The magnetic energy stored in an inductor is ______ current.
A. Directly proportional to
B. Inversely proportional to
C. Directly proportional to the square of
D. Inversely proportional to the square of
Answer : C

45. The permittivity of a material is given by one of the following formulas.
A. DE
B. E/D
C. D^2/E
D. D/E
Answer : D

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

47. 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

48. 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

49. The magnetic flux through a wire loop in a magnetic field does not d
A. T he area of the loop
B. The magnitude of the field
C. The shape of the loop
D. The angle between the plane of the loop and the direction
Answer : C

50. 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