Electricity Fundamentals 1000+ MCQ with answer for UPSC IES

1. The air space between poles of magnets
A. Air gap
B. Free space
C. Vacuum
D. Atmosphere
Answer : A

2. __________ is a substance of whose molecules consist of the same kind of atom.
A. Mixture
B. Compound
C. Element
D. Isotope
Answer : C

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

4. The ratio of the total flux (flux in iron path) to the useful flux (flux in air gap)
A. Leakage flux
B. Leakage current
C. Leakage coefficient
D. Leakage factor
Answer : D

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

6. The force between two magnetic poles is _______ their pole strengths.
A. directly proportional to
B. the sum of
C. inversely proportional to
D. the product of
Answer : A

7. 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

8. The flux density in an air-cored coil is 10^-3 Wb/m^2. With a cast iron core of relative permeability 100 inserteda the flux density will become
A. 10^-3 Wb/m^2
B. 10^-2 Wb/m^2
C. 10^3 Wb/m^2
D. 0.1 Wb/m^2
Answer : D

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

10. 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

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

12. 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

13. 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

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

15. 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

16. Paramagnetic substance has a relative permeability of
A. Slightly less than one
B. Equal to one
C. Slightly equal to one
D. Very much greater than one
Answer : C

17. Who discovered that a current-carrying conductor would move when placed in a magnetic field?
A. Michael Faraday
B. Andre Ampere
C. Hans Christian Oersted
D. Gustav Robert Kirchhoff
Answer : A

18. 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

19. Which of the following has the least number of valence electrons?
A. Conductor
B. Semiconductor
C. Insulator
D. Semi- insulator
Answer : A

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

21. 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

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

23. 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

24. The evaporation of electrons from a heated surface is called
A. Radiation
B. Convection
C. Thermionic emission
D. Conduction
Answer : C

25. 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

26. What is the practical unit of electrical energy?
A. Watt
B. Kilowatt-hour
C. Kilowatt-second
D. Megawathour
Answer : B

27. 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

28. The conduction of electricity across the surface of a dielectric is called
A. creepage
B. skin effect
C. surface effect
D. crosstalk
Answer : A

29. If the length and area of cross-section of a wire are doubleda then its resistance
A. becomes four times
B. becomes sixteen times
C. remains the same
D. becomes two times
Answer : C

30. One coulomb of charge consists of ________ electrons.
A. 624× 10^16
B. 62.4 × 10^16
C. 6.24 × 10^16
D. 0.624 × 10^16
Answer : A

31. The core of a transformer heats up when its primary is fed from an ac source because of
A. permeability
B. ferromagnetism
C. reluctance of core
D. hysteresis loss
Answer : D

32. 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

33. What is the SI unit of specific resistance or resistivity?
A. Ohm-circular mil per inch
B. Ohm-circular mil per foot
C. Ohm-m
D. Ohm-cm
Answer : C

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

35. The relative permeability of a magnetic material is 10^5. What is its permeability?
A. 4 × 10^5 H/m
B. 4 × 10^-12 H/m
C. 4× 10^-2 H/m
D. 4 × 10^7H/m
Answer : C

36. 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

37. 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

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

39. 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

40. A negatively charge body has
A. deficit of electrons
B. excess of protons
C. excess of electrons
D. deficit of neutrons
Answer : C

41. 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

42. 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

43. The permeability of a material having a flux density of 5 Wb/m^2 is 10^-5 H/m. What is the value of magnetizing force?
A. 5 × 10^-5 N/Wb
B. 500 × 10^3 N/Wb
C. 4 × 10^7N/Wb
D. 4 × 10^7N/Wb
Answer : B

44. 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

45. 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

46. Which of the following is used by temporary magnets as the magnetic material?
A. Hardened steel
B. Cobalt steel
C. Soft iron
D. Tungsten steel
Answer : C

47. What is the value of the absolute permittivity of air?
A. 8.854 F/m
B. 8.854 × 10^-12 mF/m
C. 8.854× 10^-12 F/m
D. 8.854 × 10^-12 F/m
Answer : C

48. Magnetic intensity is a
A. Phasor quantity
B. Physical quantity
C. Scalar quantity
D. Vector quantity
Answer : D

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

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