1000+ Electricity Fundamentals MCQ for GMAT [Solved]

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

2. Which of the following materials has the least hysteresis loop area?
A. soft iron
B. silicon steel
C. hard steel
D. wrought iron
Answer : B

3. 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

4. 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

5. 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

6. 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

7. A commercial alloy of aluminum nickela and iron with cobalta copper and titanium added to produce about 12 grades.
A. Alnico
B. Brass
C. Aluminum
D. Constantan
Answer : A

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

9. The energy stored in an electrostatic field or electromagnetic field is called
A. Electromagnetic energy
B. Kinetic energy
C. Potential energy
D. R est energy
Answer : C

10. 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

11. 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

12. 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

13. The property of magnetic materials of retaining magnetism after withdrawal of the magnetizing force is known as
A. Retentivity
B. Reluctivity
C. Resistivity
D. Conductivity
Answer : A

14. Why is it that the magnitude of magnetomotive force required for air gap is much greater than that required for iron part of a magnetic circuit?
A. Because air is a gas
B. Because air has the highest relative permeability
C. Because air is a conductor of magnetic flux
D. Because air has the lowest relative permeability
Answer : D

15. 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

16. 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

17. 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

18. When the current flowsa the magnetic field ��. conductor is in what direction?
A. The same as the current direction
B. Opposite the current direction
C. Omnidirectional
D. In the direction determined by the left hand rule
Answer : D

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

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

21. 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

22. Materials that have very high permeabilities (hundreds and even thousands times of that of free space)
A. Paramagnetic
B. Non- magnetic
C. Ferromagnetic
D. Diamagnetic
Answer : C

23. A germanium atom has an atomic weight of72. How many neutrons are there?
A.
B.
C.
D.
Answer : B

24. 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

25. 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

26. 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

27. A length of wire has a resistance of 10 ohms. What is the resistance of a wire of the same material three times as long and twice the cross-sectional area?
A. 30 ohms
B. 20 ohms
C. 15 ohms
D. 7 ohms
Answer : C

28. 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

29. The straight line passing through the two poles of magnet is called
A. Real axis
B. Cartesian axis
C. Magnetic axis
D. Imaginary axis
Answer : C

30. The B-H curve for ________ is a straight line passing through the origin.
A. cobalt
B. air
C. hardened steel
D. soft iron
Answer : B

31. What bond is formed when electrons in the outermost energy orbits of the atoms are shared between two or more electrons?
A. Ionic
B. Covalent
C. Metallic
D. Van der Waals
Answer : B

32. 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

33. If the value of 25 of a conductor is 1/230 per oCa then the value of 0is
A. 1/180 peroC
B. 1/150 per oC
C. 1/280 per oC
D. 1/230 per oC
Answer : A

34. The magnetic materials should have a large hysteresis loss for one of the following applications.
A. Transformers
B. ACmotors
C. Permanent Magnets
D. DC generators
Answer : C

35. A t/m is a unit of
A. Mmf
B. Emf
C. Reluctance
D. Magnetizing force
Answer : D

36. The total number of magnetic lines of force in a magnetic field is called
A. Magnetic flux
B. Magnetic flux density
C. Magnetic flux intensity
D. Magnetic potential
Answer : A

37. The force of attraction or repulsion between two magnetic poles is directly proportional to their strengths.
A. Newton's first law
B. Faraday's first law of electromagnetic induction
C. Coulomb's first law
D. Coulomb's second law
Answer : C

38. 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

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

40. 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

41. 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

42. 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

43. 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

44. The ratio of the permeability of material to the permiabiity of air or vacuum.
A. Relative permeability
B. Relative permittivity
C. Relative conductivity
D. Relative reluctivity
Answer : A

45. 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

46. The magnitude of the induced emf in a coil is directly proportional to the rate of change of flux linkages. This is known as
A. Joule's Law
B. Faraday's second law of electromagnetic induction
C. Faraday's first law of electromagnetic induction
D. Coulomb's Law
Answer : B

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

48. 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

49. Steel is hard to magnetize because of its
A. Low permeability
B. High permeability
C. High density
D. High retentivity
Answer : A

50. 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