1000+ Electricity Fundamentals MCQ for JEE Main [Solved]

1. Hydrogen is an example of a _____ material.
A. Paramagnetic
B. Diamagnetic
C. Ferromagnetic
D. N on- magnetic
Answer : B

2. 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

3. The amount of magnetizing force to counter balance the resid magnetic material is referred to as
A. Reluctivity
B. Susceptivity
C. Coercivity
D. Retentivity
Answer : C

4. 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

5. 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

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

7. 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

8. The ability of a mechanically stressed ferromagnetic wire to recognize rapid switching of magnetization when subjected to a dc magnetic field.
A. Wartheim effect
B. Wiedemann effect
C. Wiegand effect
D. Edison effect
Answer : C

9. The temperature coefficient of resistance of eureka is
A. p ositive
B. negative
C. almost zero
D. i nfinite
Answer : C

10. 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

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

13. 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

14. 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

15. Permanent magnets can be found in
A. electric bells
B. earphones
C. relays
D. dy namic loudspeakers
Answer : B

16. One ampere- turn is equivalent to _____ gilberts
A.
B.
C.
D.
Answer : B

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

18. Magnetic field intensity is a ________ quantity.
A. scalar
B. phasor
C. vector
D. variable
Answer : C

19. 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

20. One oersted (Oe) is equivalent to _____ Gb/cm.
A.
B.
C.
D.
Answer : A

21. Defined as a closed path in which magnetic induction or flux flows
A. Electric circuit
B. Magnetic circuit
C. Electronic circuit
D. Electromagnetic circuit
Answer : B

22. The magnetic potential in a magnetic circuit can be measured in terms of
A. Mmf
B. Emf
C. Farad
D. Coulomb
Answer : A

23. 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

24. 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

25. 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

26. 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

27. The contribution to the ionization in an ionization chamber by electrons liberated from t he walls.
A. Skin effect
B. Walt effect
C. Hall effect
D. Edison effect
Answer : B

28. 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

29. 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

30. If the number of valence electrons of an atom is less than 4a the substance is called
A. a conductor
B. a semiconductor
C. an insulator
D. a superconductor
Answer : A

31. 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

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

33. 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

34. 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

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

36. Back emf refers to the
A. Current equal to the applied emf
B. Opposing emf
C. Current opposing the applied emf
D. Voltage opposing the applied emf
Answer : D

37. The emf produced in a wire by its motion across a magnetic field does not depend upon the
A. Diameter of the wire
B. Length of the wire
C. Orientation of the wire
D. Flux density of the field
Answer : A

38. If the distance between two magnetic poles decreases by 2 timesa the force between them
A. decreases two times
B. increases four times
C. increases two times
D. decreases four times
Answer : B

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

40. 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

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

42. 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

43. 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

44. 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

45. Temporary magnets are commonly employed in
A. electric instruments
B. motors
C. moving coils loudspeakers
D. magnetos
Answer : B

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

47. Bonding of atoms that is due to the force of attraction between positive ions and a group of negative ions
A. Ionic bond
B. Covalent Bond
C. Electrostatic Bond
D. Metallic bond
Answer : D

48. 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

49. How many turns are needed to produce a magnetomotive force of 1000 A.t for a coil with 6 amperes?
A. 6000 turns
B. 600 turns
C. 167 turns
D. 67turns
Answer : C

50. What is the typical saturation flux density for most magnetic materials?
A. 4 Wb/m^2
B. 5 Wb/m^2
C. 1 Wb/m^2
D. 2 Wb/m^2
Answer : D