LIC AAO - Electricity Fundamentals 1000+ MCQ [Solved] PDF Download

1. What is the unit of magnetomotive force?
A. Volt
B. Tesla
C. Ampere- turn
D. Weber
Answer : C

2. What determines the value of the temperature coefficient of resistance of a material?
A. length
B. cross-sectional area
C. volume
D. nature and temperature
Answer : D

3. Which of the following statements is TRUE?
A. Silicon dioxide is a good
B. The current carriers in conductors are valence electrons
C. For conductorsa the valence electron are strongly attracted to the nucleus
D. The valence electrons are located in the nucleus of an atom
Answer : B

4. 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

5. The permeability of permalloy is
A. Very much greater than permeability of air
B. Slightly greater than permeability of air
C. Slightly less than permeability of air
D. Equal to the permeability of air
Answer : A

6. Hipernik is an alloy containing __________ iron and __________ nickel.
A. 40% ; 60%
B. 60% ; 40%
C. 50% ; 50%
D. 70% ; 30%
Answer : A

7. Who demonstrated that there are magnetic effects around every current-carrying conductor and that current-carrying conductors can attract and repel each other just like magnets?
A. Luigi Galvani
B. Hans Christian Oersted
C. Charles Coulomb
D. Andre Ampere
Answer : D

8. 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

9. 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

10. 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

11. 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

12. ______ 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

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

14. The unit of electrical energy is
A. Joule
B. Watt- second
C. Kilowatt hour
D. All of these
Answer : D

15. The emf induced in a coil due to the changing current of another neighboring coil is called
A. Mutually induced emf
B. Self induced emf
C. Statically induced emf
D. Dynamically induced emf
Answer : A

16. A law stating that the magnetic susceptibilities of most paramagnetic substances are inversely proportional to their absolute temperatures.
A. Curie's Law
B. Child's Law
C. CR Law
D. Curie-Weiss Law
Answer : A

17. 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

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

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

20. The force between two charges placed a given distance apart ______ as the relative permittivity of the medium is increased.
A. increases
B. decreases
C. remains unchanged
D. becomes infinite
Answer : B

21. 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

22. 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

23. 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

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

25. Who demonstrated the theory of electromagnetic induction in 1831?
A. Michael Faraday
B. Andre Ampere
C. James Clerk Maxwell
D. Charles Coulomb
Answer : A

26. Electric field intensity is a ________.
A. scalar
B. phasor
C. vector
D. variable
Answer : C

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

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

29. How much is the flux in Weber in the above problem?
A. 2 x 10^-5
B. 2 x 10^-3
C. 2 x 10^5
D. 2 x 10^3
Answer : A

30. 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

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

32. 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

33. When a conductor is stationary and the magnetic field is moving or changing the emf induced is called
A. Statically induced emf
B. Mutually induced emf
C. Self induced emf
D. Dynamically induced emf
Answer : A

34. One oersted (Oe) is equivalent to _____ Gb/cm.
A.
B.
C.
D.
Answer : A

35. 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

36. 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

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

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

39. What is the SI unit of conductivity?
A. Ohms/m
B. Ohms-m
C. Siemens-m
D. Siemens/m
Answer : D

40. The K shell or the first shell has how many permissible number of orbiting electrons?
A.
B.
C.
D.
Answer : B

41. 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

42. Whenever a conductor cuts magnetic fluxa an emf is induced in it. This is known as
A. Coulomb's law
B. Joule's law
C. Faraday's law
D. Ohm's law
Answer : C

43. A magnetic circuit carries a flux iin the iron part and a fluxgin the air gap. What is the leakage coefficient?
A. i/g
B. i × g
C. g/ i
D. i + g
Answer : A

44. 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

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

46. The greater percentage of materials is _________.
A. diamagnetic
B. paramagnetic
C. ferromagnetic
D. non-magnetic
Answer : B

47. 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

48. 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

49. A magnetic field is
A. The current flow through space around a permanent magnet
B. The force set up when current flows through a conductor
C. The force that drives current through a resistor
D. The force between the plates of a charged capacitor
Answer : B

50. 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