Electricity Fundamentals 1000+ MCQ with answer for LSAT

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

2. 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

3. 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

4. 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

5. The magnetic field around the conductor is determined by the
A. Size of the conductor
B. Amount of current
C. Current divided by the resistance
D. Resistance divided by the current
Answer : B

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

7. 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

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

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

10. Electric potential is a _______ quantity.
A. scalar
B. phasor
C. vector
D. variable
Answer : A

11. Which of the following is a vector quantity?
A. Magnetic potential
B. Magnetic field intensity
C. Magnetic permeability
D. F lux density
Answer : B

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

13. 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

14. Bonding of atoms that is due to the force of attraction between positive ions and a group of negative ions
A. Ionic bond
B. Covalent Bond
C. Electrostatic Bond
D. Metallic bond
Answer : D

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

16. Refers to the non- metallic materials that have the ferromagnetic properties of iron.
A. Ferrites
B. Ferromagnetic
C. Diamagnetic
D. Paramagnetic
Answer : A

17. 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

18. 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

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

20. 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

21. The amount of magnetizing force to counter balance the resid magnetic material is referred to as
A. Reluctivity
B. Susceptivity
C. Coercivity
D. Retentivity
Answer : C

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

23. ______ 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

24. 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

25. A law relating between the magnetic and electric susceptibilities and the absolute temperatures which is followed b ferromagnetsa antiferromagnetsa non-polar ferroelectricsa antiferroelectrics and some paramagnets.
A. Curie's Law
B. Child's Law
C. CR Law
D. Curie-Weiss Law
Answer : D

26. A principle that states that only two electrons with different spins are allowed to exist in a given orbit
A. Bohr's principle
B. Pauli exclusion principle
C. Avogadro's principle
D. Coulomb's principle
Answer : B

27. One that has magnetic poles produced by internal atomic structure with no external current necessary
A. Diamagnetic
B. Permanent magnets
C. Paramagnetic
D. Electromagnetic
Answer : B

28. When a current carrying conductor is placed in a magnetic fielda the maximum force will act on the conductor when the conductor is at an angle of _______ to the magnetic field.
A. 45o
B. 60o
C. 30o
D. 90o
Answer : D

29. One electron volt (1 eV) is equivalent to _____ joules
A. 1.3 x 10^-19
B. 1.4 x 10^-19
C. 1.5 x 10^-19
D. 1.6 x 10^-19
Answer : D

30. Who discovered the most important electrical effects which is the magnetic effect?
A. Hans Christian Oersted
B. Sir Charles Wheatstone
C. Georg Ohm
D. James Clerk Maxwell
Answer : A

31. The electric field intensity between the parallel plate air capacitor is 20 N/C. If an insulating slab of relative permittivity 5 is placed between the platesa then electric field intensity will be
A. 20 N/C
B. 100 N/C
C. 4N/C
D. 40 N/C
Answer : C

32. 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

33. 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

34. One of the common application of an air- cored choke.
A. Radio frequency
B. Audio frequency
C. Power supply
D. Power transformer
Answer : A

35. The simplest type of atom to exist is the ______ atom.
A. Helium
B. Hydrogen
C. Boron
D. Oxygen
Answer : B

36. 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

37. 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

38. 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

39. 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

40. Permeance is analogous to
A. Conductance
B. Reluctance
C. Admittance
D. Resistance
Answer : A

41. Who developed the electromagnetic theory of light in 1862?
A. Heinrich Rudolf Hertz
B. Wilhelm Rontgen
C. James Clerk Maxwell
D. Andre Ampere
Answer : C

42. All matters (gasa liquid and solid) are composed of
A. Neutrons
B. Particles
C. Electrons
D. Atoms
Answer : D

43. If the number of valence electrons of an atom is less than 4a then the substance is probably
A. a metal
B. an insulator
C. a non-metal
D. a semiconductor
Answer : A

44. If the magnetic material is located within a coil through which alternating current (60 Hz frequency) flowsa then __________ hysteresis loops will be formed
A.
B.
C.
D.
Answer : A

45. 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

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

47. 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

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

49. What is the measure of the density and sign of the electric charge at a point relative to that at some time?
A. Electric potential
B. Electric charge
C. Electric current
D. Electric intensity
Answer : A

50. 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