SSC JE Exam - magnetic circuits flux mmf reluctance electromagnetic induction self mutual induction Online Test (MCQ Quiz)

1. What is the unit of magnetic flux?

A) Ampere-turn B) Weber C) Henry D) Ohm

2. The magnetic equivalent of Ohm's law in an electric circuit is:

A) Flux = MMF / Reluctance B) MMF = Flux * Reluctance C) Reluctance = Flux / MMF D) MMF = Flux / Reluctance

3. Reluctance of a magnetic circuit is analogous to which property of an electric circuit?

A) Conductance B) Resistance C) Inductance D) Capacitance

4. What does MMF stand for in the context of magnetic circuits?

A) Magnetic Field Magnitude B) Magnetomotive Force C) Maximum Magnetic Energy D) Mutual Magnetic Flux

5. Which law states that a voltage is induced in a conductor when it is exposed to a changing magnetic field?

A) Ampere's Law B) Faraday's Law of Electromagnetic Induction C) Lenz's Law D) Coulomb's Law

6. Lenz's Law is a consequence of the conservation of:

A) Charge B) Energy C) Momentum D) Mass

7. What is the unit of reluctance?

A) Weber/Ampere-turn B) Ampere-turn/Weber C) Weber-turn/Ampere D) Ampere/Weber-turn

8. Self-induction is the phenomenon where a changing current in a coil induces an EMF in:

A) An adjacent coil B) The same coil C) A nearby conductor D) The earth

9. Mutual induction occurs when a changing current in one coil induces an EMF in:

A) The same coil B) An adjacent coil C) A separate, non-magnetic circuit D) A parallel coil with no magnetic coupling

10. The coefficient of self-inductance (L) of a coil is defined as the ratio of:

A) Flux linkage to current B) Current to flux linkage C) Induced EMF to current D) Current to induced EMF

11. The coefficient of mutual inductance (M) between two coils is defined as the ratio of:

A) Flux linkage in coil 1 to current in coil 2 B) Flux linkage in coil 2 to current in coil 1 C) Flux linkage in one coil to current in the other coil D) Induced EMF in one coil to current in the other coil

12. What is the unit of inductance (both self and mutual)?

A) Farad B) Ohm C) Henry D) Tesla

13. For a given magnetic circuit, if the MMF is doubled and the reluctance is halved, the magnetic flux will:

A) Remain the same B) Double C) Quadruple D) Become one-fourth

14. Which property of a material opposes the establishment of magnetic flux within it?

A) Permeability B) Conductivity C) Reluctance D) Susceptibility

15. Permeability of a material is analogous to which property of an electric circuit?

A) Resistance B) Conductance C) Resistivity D) Conductivity

16. The magnetic flux density (B) is defined as:

A) Total magnetic flux B) Magnetic flux per unit area C) MMF per unit length D) Magnetic field intensity

17. What is the unit of magnetic flux density?

A) Weber B) Tesla C) Ampere-turn D) Henry

18. If the number of turns in a coil is doubled, and the current remains the same, the MMF produced will:

A) Halve B) Remain the same C) Double D) Quadruple

19. The induced EMF in a coil is proportional to the rate of change of:

A) Current B) Resistance C) Flux linkage D) Voltage

20. The energy stored in an inductor is given by the formula:

A) 1/2 * L * V^2 B) 1/2 * C * V^2 C) 1/2 * L * I^2 D) 1/2 * R * I^2

21. Which of the following factors affects the self-inductance of a coil?

A) Number of turns, core material, and geometry B) Applied voltage only C) Resistance of the wire only D) Frequency of the current only

22. The coefficient of coupling (k) between two coils is a measure of:

A) Their individual inductances B) The ratio of mutual inductance to the geometric mean of self-inductances C) The ratio of self-inductance to mutual inductance D) The total inductance of the combination

23. If k = 1 for two coils, it means there is:

A) No magnetic coupling B) Partial magnetic coupling C) Perfect magnetic coupling D) Zero mutual inductance

24. When magnetic flux passes through a core material, the material's property that facilitates this passage is called:

A) Resistivity B) Conductivity C) Permeability D) Permittivity

25. A changing magnetic field can induce an electric field. This is the principle behind:

A) Electrostatics B) Electromagnetic induction C) Conduction current D) Dielectric polarization

26. For a magnetic circuit made of a material with high permeability, the reluctance will be:

A) High B) Low C) Zero D) Infinite

27. The unit of magnetic field intensity (H) is:

A) Ampere-turn/meter B) Weber/meter^2 C) Ampere/meter D) Henry/meter

28. Magnetic flux linkage is defined as:

A) Total magnetic flux B) Magnetic flux multiplied by the number of turns C) Magnetic flux density times area D) MMF divided by reluctance

29. In a series magnetic circuit, the total reluctance is:

A) The sum of individual reluctances B) The product of individual reluctances C) The average of individual reluctances D) The reciprocal of the sum of individual reluctances

30. What is the relationship between magnetic field intensity (H) and magnetic flux density (B) in a linear magnetic medium?

A) B = H / μ B) B = μ * H C) H = B * μ D) B = μ / H

31. The term 'air gap' in a magnetic circuit typically implies:

A) A region of high permeability material B) A region of very low reluctance C) A region of low permeability (like air) inserted into the magnetic path D) A region where MMF is generated

32. Which of the following statements about Faraday's Law is correct?

A) It describes the force on a current-carrying conductor in a magnetic field. B) It relates the induced EMF to the rate of change of magnetic flux. C) It defines the magnetic field produced by a current. D) It explains the behavior of magnetic poles.

33. If a coil has an inductance of 10 H and carries a current of 2 A, the magnetic flux linkage is:

A) 5 Weber-turns B) 20 Weber-turns C) 10 Weber-turns D) 4 Weber-turns

34. The phenomenon of electromagnetic induction is fundamentally described by:

A) Maxwell's Equations B) Ohm's Law C) Kirchhoff's Laws D) Coulomb's Law

35. A changing current in coil 1 induces an EMF in coil 2. This is an example of:

A) Self-induction B) Mutual induction C) Capacitive coupling D) Resonant induction

36. The reluctance of a magnetic circuit depends on:

A) The length of the magnetic path and the cross-sectional area B) The permeability of the material C) Both (a) and (b) D) The applied MMF only

37. If the flux in a magnetic circuit remains constant, but the current in the coil producing it changes, what is the induced EMF?

A) Maximum B) Minimum C) Zero D) Dependent on reluctance

38. Which of the following is NOT a unit of magnetic flux?

A) Weber B) Gauss C) Maxwell D) Tesla

39. The relationship M = k * sqrt(L1 * L2) defines:

A) The total inductance of two coils in series B) The mutual inductance between two coils C) The self-inductance of a single coil D) The equivalent resistance of two coupled inductors

40. Eddy currents are induced in:

A) Insulating materials B) Conducting materials subjected to changing magnetic fields C) Non-magnetic materials D) Vacuum

41. For a toroidal coil with N turns, a core length of l, and cross-sectional area A, carrying current I, the MMF is approximately:

A) N * I B) N * I / l C) μ * N * I / l D) B * A

42. The property of a material that opposes the change of magnetic flux is:

A) Conductance B) Inductance C) Reluctance D) Permeance

43. If the reluctance of a magnetic circuit increases, and MMF is constant, the magnetic flux will:

A) Increase B) Decrease C) Remain the same D) Become zero

44. What is the unit of magnetic flux linkage?

A) Weber B) Weber-turn C) Ampere-turn D) Henry

45. Which law is used to determine the direction of the induced EMF?

A) Ampere's Law B) Faraday's Law C) Lenz's Law D) Biot-Savart Law

46. The ratio of magnetic flux (Φ) to MMF is:

A) Permeance B) Reluctance C) Permittivity D) Conductivity

47. If two coils have inductances L1 and L2 and are wound on a common core with coefficient of coupling k, their equivalent inductance when connected in series aiding is:

A) L1 + L2 B) L1 + L2 + 2k * sqrt(L1*L2) C) L1 + L2 + 2 * sqrt(L1*L2) D) L1 + L2 - 2k * sqrt(L1*L2)

48. The magnetic flux density in a material is the sum of the magnetic field intensity and the:

A) Magnetic susceptibility B) Magnetic permeability C) Magnetization vector (M) D) Magnetic reluctance

49. What is the condition for resonance in an RLC circuit, which involves magnetic and electric fields?

A) XL = XC B) R = 0 C) XL = R D) XC = R

50. The induced voltage in a moving conductor is given by v = Blv, where B is the magnetic flux density, l is the length of the conductor, and v is the velocity. This is a direct application of:

A) Ampere's Law B) Lenz's Law C) Faraday's Law of Induction D) Biot-Savart Law

magnetic circuits flux mmf reluctance electromagnetic induction self mutual induction - Online Test

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