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1000+ Electricity Fundamentals Multiple Choice Question Answer [Solved]

Thursday 9th of March 2023

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1. 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
2. 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
3. Magnetic field intensity is a ________ quantity.
A. scalar
B. phasor
C. vector
D. variable
Answer : C
4. Which of the following is a diamagnetic material?
A. Aluminum
B. Silver
C. Air
D. Cobalt
Answer : C
5. 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
6. A negatively charge body has
A. deficit of electrons
B. excess of protons
C. excess of electrons
D. deficit of neutrons
Answer : C
7. The science of adapting electronics to aerospace flight.
A. Avionics
B. Aerotronics
C. Aerodynamics
D. Astrionics
Answer : D
8. 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
9. 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
10. The electric potential at a point in air due to a charge is 21 V. If the air is replaced by a medium of relative permittivity of 3a then electric potential at that point will be
A. 63 V
B. 21 V
C. 7 V
D. 42 V
Answer : C
11. Materials whose permeabilities are slightly greater than that of free space
A. Paramagnetic
B. Non- magnetic
C. Ferromagnetic
D. Diamagnetic
Answer : A
12. Who demonstrated the theory of electromagnetic induction in 1831?
A. Michael Faraday
B. Andre Ampere
C. James Clerk Maxwell
D. Charles Coulomb
Answer : A
13. What is the SI unit of reluctance?
A. At
B. At/m
C. N/Wb
D. At/Wb
Answer : D
14. 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
15. 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
16. Who discovered superconductivity in 1911?
A. Kamerlingh Onnes
B. Alex Muller
C. GeoryBednorz
D. Charles Coulomb
Answer : A
17. The tiniest element of matter
A. Atom
B. Proton
C. Electron
D. Neutron
Answer : A
18. What is the other name for dielectric strength?
A. Breakdown voltage
B. Electric intensity
C. Potential gradient
D. Dielectric constant
Answer : A
19. A t/m is a unit of
A. Mmf
B. Emf
C. Reluctance
D. Magnetizing force
Answer : D
20. Permeance of a magnetic circuit is _________ the cross-sectional area of the circuit.
A. directly proportional to
B. inversely proportional to
C. dependent of
D. independent of
Answer : A
21. 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
22. 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
23. 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
24. The temperature coefficient of resistance of insulators is
A. zero
B. negative
C. positive
D. infinite
Answer : B
25. 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
26. 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
27. Refers to the magnetic lines
A. Flux
B. Hysteresis
C. Current
D. Magnetomotive force
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 unit of electrical energy is
A. Joule
B. Watt- second
C. Kilowatt hour
D. All of these
Answer : D
30. An alloy of 40 percent iron and 60 percent nickel.
A. Alnico
B. Permalloy
C. Hipernik
D. Manganin
Answer : C
31. If the resistance of a material 2 m long and 2 m^2 in area of cross-section is 1.6 ×10^-8 ?a then its resistivity is
A. 3.2 × 10^-8 ?-m
B. 1.6 × 10^-8 ?-m
C. 0.64 × 10^-8 ?-m
D. 0.16 × 10^-8 ?-m
Answer : B
32. 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
33. 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
34. 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
35. A law establishing the fact that the algebraic su of the rises and drops of the mmf around a closed loop of a magnetic circuit is equal to zero.
A. Kirchhoff's circuital law
B. Maxwell's circuital law
C. Ampere's circuital law
D. Coulomb's circuital law
Answer : C
36. This paper does not exhibit electricity because it contains the same number of
A. protons and electrons
B. neutrons and electrons
C. neutrons and positrons
D. atoms
Answer : A
37. ______ 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
38. Electronic current in a wire is the flow of ____________ electrons.
A. free
B. valence
C. bound
D. loose
Answer : A
39. Another term for corona discharge.
A. Lightning
B. Sparking
C. Aurora
D. Corona Effect
Answer : C
40. 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
41. Steel is hard to magnetize because of its
A. Low permeability
B. High permeability
C. High density
D. High retentivity
Answer : A
42. 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
43. Flux linkages equals
A. Flux times area of core
B. Flux times number of turns times area of core
C. Flux times number of turns times length of core
D. Flux times number of turns
Answer : D
44. 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
45. 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
46. What is the maximum number of electrons that can be accommodated in the last orbit of an atom?
A.
B.
C.
D.
Answer : C
47. A magnetic material losses its ferromagnetic properties at a point called
A. Curie temperature
B. Inferred absolute temperature
C. Room temperature
D. Absolute temperature
Answer : A
48. One oersted (Oe) is equivalent to _____ Gb/cm.
A.
B.
C.
D.
Answer : A
49. 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
50. The phenomenon that when an electric current passes through an anisotropic crystala there is an absorption or liberation of heat due to the non-uniformity in current distribution.
A. Bridgman effect
B. Corona effect
C. Dember effect
D. Destriau effect
Answer : A

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