Electricity Fundamentals 1000+ MCQ with answer for ISRO Recruitment

1. 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

2. The electric potential across part AB of a circuit is 5 V; point A being at higher potential. If a charge of 5 Cmoves from A to Ba then energy released as
A. 5 joules
B. 25 joules
C. 10 joules
D. 100 joules
Answer : B

3. The quantity of magnetism retained by a magnetic material after withdrawal of the magnetizing force is called
A. Leftover magnetism
B. Hysteresis
C. Residual magnetism
D. Coercivity
Answer : C

4. When the ferromagnetic substance is inserted in a current- carrying solenoida the magnetic field is
A. Greatly decreased
B. Greatly increased
C. Slightly decreased
D. Slightly increased
Answer : B

5. 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

6. 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

7. 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

8. 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

9. The reluctance of the magnetic circuit is ________ relative permeability of the material comprising the circuit.
A. directly proportional to
B. inversely proportional to
C. independent of
D. dependent of
Answer : B

10. A one cubic cm of copper has how many free electrons at room temperature?
A. 80 × 10^18
B. 8.5 × 10^22
C. 20 × 10^10
D. 50 × 10^20
Answer : B

11. Define as that pole which when placed in air from a similar and equal pole repels it with a force of newtons
A. North pole
B. South pole
C. Unit pole
D. Magnetic pole
Answer : C

12. 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

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

14. The K shell or the first shell has how many permissible number of orbiting electrons?
A.
B.
C.
D.
Answer : B

15. The force between two magnetic poles is _____ the relative permeability of the medium.
A. directly proportional to
B. independent of
C. inversely proportional to
D. equal to
Answer : C

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

17. What solid has no defined crystal structure except perhaps in the arrangement of the nearest neighboring atoms or ions?
A. Crystalline
B. Amorphous
C. Polycrystalline
D. Poly amorphous
Answer : B

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

19. Hipernik is an alloy containing __________ iron and __________ nickel.
A. 40% ; 60%
B. 60% ; 40%
C. 50% ; 50%
D. 70% ; 30%
Answer : A

20. 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

21. 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

22. 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

23. What principle states that each electron in an atom must have a different set of quantum numbers?
A. Inclusion principle
B. Exclusion principle
C. Quantum principle
D. Electron principle
Answer : B

24. The property of a material which opposes the creation of magnetic flux in it
A. Resistance
B. Reluctance
C. Permeance
D. Conductance
Answer : B

25. 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

26. Lenz's law is the consequence of the law of conservation of
A. Energy
B. Charge
C. Field lines
D. Momentum
Answer : A

27. What is used as the dielectric material in high voltage transformers?
A. Mica
B. Paraffin
C. Porcelain
D. Oiled paper
Answer : C

28. A substance that attracts pieces iron
A. Conductor
B. Semiconductor
C. Magnet
D. All of the above
Answer : C

29. 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

30. 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

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

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

33. 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

34. 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

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

36. Electric lines of force leave or enter the charge surface at an angle of
A. 30o
B. 45 o
C. 90o
D. depending upon the angle of launch and entry
Answer : C

37. 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

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

39. The force between two magnetic poles varies with the distance between them. The variation is ______ to the square of that distance.
A. Equal
B. Greater than
C. Directly proportional
D. Inversely proportional
Answer : D

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

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

42. What is the diameter of an atom?
A. About 10^-10 m
B. About 10^-10 cm
C. About 10^-10 mm
D. About 10^-10 �m
Answer : A

43. 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

44. The diameter of a hydrogen atom is approximately ______ cm.
A. 1.1 x 10^-6
B. 1.1 x 10^7
C. 1.1 x 10^-8
D. 1.1 x 10^-9
Answer : C

45. The unit of electrical energy is
A. Joule
B. Watt- second
C. Kilowatt hour
D. All of these
Answer : D

46. Electronic current in a wire is the flow of ____________ electrons.
A. free
B. valence
C. bound
D. loose
Answer : A

47. The mass of proton is __________ the mass of an electron.
A. equal to
B. about 1837 times
C. less than
D. 200 tim es
Answer : B

48. A test charge means a charge of
A. -1 C
B. 1 electron
C. +1 C
D. -20 C
Answer : C

49. When a conductor is stationary and the magnetic field is moving or changing the emf induced is called
A. Statically induced emf
B. Mutually induced emf
C. Self induced emf
D. Dynamically induced emf
Answer : A

50. The force which set ups or tends to set up magnetic flux in a magnetic circuit
A. Dynamic force
B. Electromotive force
C. Potential difference
D. Magnetomotive force
Answer : D