Electricity Fundamentals 1000+ MCQ with answer for DRDO

1. Permeability means
A. The conductivity of the material for magnetic lines of force
B. The magnetization test in the material after exciting field has been removed
C. The strength of an electromagnet
D. The strength of the permanent magnet
Answer : A

2. Small voltages generated by a conductor with current in an external magnetic field.
A. Skin effect
B. Magnetic effect
C. Hall effect
D. Flywheel Effect
Answer : C

3. 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

4. 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

5. 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

6. Referred to as the specific reluctance of a material
A. Resistivity
B. Reluctivity
C. Conductivity
D. Permeability
Answer : B

7. 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

8. An alloy of 40 percent iron and 60 percent nickel.
A. Alnico
B. Permalloy
C. Hipernik
D. Manganin
Answer : C

9. 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

10. The reluctance of a magnetic circuit is not dependent on which of the following?
A. Number of turns of coil
B. Magnetomotive force
C. Flux density in the circuit
D. Current in the coil
Answer : C

11. 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

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

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

14. The space outside the magnet where its pole have a force of attraction or repulsion on a magnetic pole is called
A. Magnetic field
B. Electric field
C. Electromagnetic field
D. Free Space Field
Answer : A

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

16. Cobalt is an example of a ______ material.
A. Paramagnetic
B. Diamagnetic
C. Ferromagnetic
D. Non- magnetic
Answer : C

17. Defined as the flux density produced in it due to its own induced magnetism
A. Magnetic field intensity
B. Electric field intensity
C. Electromagnetic field intensity
D. Intensity magnetization
Answer : D

18. 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

19. 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

20. 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

21. Which of the following materials has permeability slightly less than that of free space?
A. Paramagnetic
B. Non- magnetic
C. Ferromagnetic
D. Diamagnetic
Answer : C

22. 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

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

24. The net electrical charge in an isolated system remains constant. This is known as
A. Law of conservation of charge
B. Coulomb's first law
C. Coulomb's second law
D. Law of conservation of energy
Answer : A

25. Hysteresis refers to the ______ between flux density of the material and the magnetizing force applied.
A. Leading effect
B. Ratio
C. Equality
D. Lagging effect
Answer : D

26. The conduction of electricity across the surface of a dielectric is called
A. creepage
B. skin effect
C. surface effect
D. crosstalk
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. The lagging effect between flux density of the material and the magne
A. Permeance
B. Eddy current
C. Hysteresis
D. R eluctance
Answer : C

29. 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

30. 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

31. 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

32. The electric flux density is a ________ quantity.
A. phasor
B. vector
C. scalar
D. variable
Answer : B

33. 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

34. Which of the following has the highest permeability?
A. Soft iron
B. Steel
C. Air
D. Permalloy
Answer : D

35. The emission of electrons from hot bodies is called
A. Radiation effect
B. Edison effect
C. Skin effect
D. Half effect
Answer : B

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

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

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

39. Refers to the magnetic lines
A. Flux
B. Hysteresis
C. Current
D. Magnetomotive force
Answer : A

40. As the magnetic intensity decreasesa the relative permeability of a magnetic material
A. decreases
B. remains the same
C. increases
D. becomes zero
Answer : C

41. An effect which is generally used in the gausameter to measure flux density.
A. Skin effect
B. Magnetic effect
C. Hall effect
D. Flywheel effect
Answer : C

42. A current if flowing east along a power line. If the earth's field is neglecteda the direction of the magnetic field below it is
A. North
B. South
C. East
D. West
Answer : A

43. The uncharged particles which have no effect on its atomic charge.
A. Nucleons
B. Electrons
C. Protons
D. Neutrons
Answer : D

44. 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

45. Electric field intensity at a point is numerically equal to ________ at that point.
A. potential gradient
B. potential difference
C. dielectric constant
D. the force
Answer : D

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

47. The magnetic flux of 2000 lines is how many Maxwells?
A.
B.
C.
D.
Answer : B

48. The emf induced in a coil due to the change of its own flux linked with it is called
A. Mutually induced emf
B. Dynamically induced emf
C. Statically induced emf
D. Self induced emf
Answer : D

49. At/m is a unit of
A. mmf
B. magnetic force
C. reluctance
D. magnetic flux density
Answer : B

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