1000+ Electricity Fundamentals MCQ for SSC CPO [Solved]

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

2. What is another name for relative permittivity?
A. Dielectric strength
B. Electric intensity
C. Potential gradient
D. Dielectric constant
Answer : D

3. Who demonstrated that there are magnetic effects around every current-carrying conductor and that current-carrying conductors can attract and repel each other just like magnets?
A. Luigi Galvani
B. Hans Christian Oersted
C. Charles Coulomb
D. Andre Ampere
Answer : D

4. If on looking at any one end of a solenoid; the direction of current flow is found to be clockwise then the end under observation is a south pole. This is known as
A. Right hand rule
B. Left hand rule
C. Cork screw rule
D. End Rule
Answer : D

5. What is the unit of magnetomotive force?
A. Volt
B. Tesla
C. Ampere- turn
D. Weber
Answer : C

6. 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

7. 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

8. 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

9. Used to maintain strength of magnetic field
A. Container
B. Air gap
C. Keeper
D. S ource
Answer : C

10. Gases whose particles are charged are known as
A. Conductors
B. Insulators
C. Gaseous Conductors
D. Plasma
Answer : D

11. The magnetic flux through a coil changes. This results to the induced emf acting in a direction as to
A. Oppose the change
B. Aid the change
C. Either oppose or aid the change
D. Neither oppose nor aid the change
Answer : A

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

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

14. The hot resistance of an incandescent lamp is about _______ its cold resistance.
A. 10 times
B. 100 times
C. 5 times
D. 50 times
Answer : A

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

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

17. The resistivity of a conductor ___________ with an increase in temperature.
A. increases
B. decreases
C. remains the same
D. becomes zero
Answer : A

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

19. The unit of flux density is
A. Wb/m
B. Tesla
C. At/m
D. N/Wb
Answer : B

20. What revolves about the positive nucleus in a definite orbit?
A. Atom
B. Proton
C. Electron
D. Neutron
Answer : C

21. What is the SI unit of magnetic flux?
A. Tesla
B. Weber
C. Maxwell
D. Gauss
Answer : B

22. 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

23. 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

24. 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

25. 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

26. 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

27. It is the reciprocal of reluctance and implies the case of readiness with which magnetic flux is developed.
A. R esistance
B. Conductance
C. Permeance
D. I nductance
Answer : C

28. 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

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. What determines the atomic number of an element?
A. The number of protons
B. The number of electrons
C. The number of neutrons
D. The number of neutrons and protons
Answer : A

31. 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

32. 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

33. 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

34. 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

35. The tiniest element of matter
A. Atom
B. Proton
C. Electron
D. Neutron
Answer : A

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

37. 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

38. 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

39. If you hold the conductor with right hand so that the stretched thumb points in the direction of the currenta then encircling fingers will give the direction of magnetic lines of force round the conductor. This is known as
A. Left hand cork screw rule
B. Right hand cork screw rule
C. Left hand rule
D. Right hand rule
Answer : D

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. When the relative permeability of a material is slightly more than 1a it is called ______ material.
A. diamagnetic
B. ferromagnetic
C. paramagnetic
D. non-magnetic
Answer : C

42. 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

43. 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

44. 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

45. The reluctance of a magnetic circuit varies with
A. length × area
B. area � length
C. length � area
D. length + area
Answer : C

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

47. The idea of preventing one component from affecting another through their common electric and magnetic field is referred to as
A. Hall effect
B. Grounding
C. Shielding
D. Limiting
Answer : C

48. The point in a magnet where the intensity of magnetic lines of force is maximum
A. Magnetic pole
B. South pole
C. North pole
D. Unit pole
Answer : A

49. 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

50. The emf induced in a coil due to the changing current of another neighboring coil is called
A. Mutually induced emf
B. Self induced emf
C. Statically induced emf
D. Dynamically induced emf
Answer : A