MCQ of Basic Electrical page-4

31. Property of a material which opposes the production of magnetic flux in it is called

a) mmf reluctance
c) permeance
d) Permittivity

32. Unit of mmf is AT
b) Weber/ampere
c) Henry
d) AT/m

33. Conductance is analogous to

a) Reluctance
b) M.m.f Permeance
d) Inductance

34. An air gap is usually inserted in magnetic circuits to Prevent saturation.
b) Increase in mmf.
c) Increase in flux.
d) Increase in inductance.

35. Permeability is reciprocal of Reluctivity
b) Susceptibility
c) Permittivity
d) Conductivity

36. The magnetic reluctance of a magnetic circuit decreases with

a) Decrease in cross-sectional area. Increase in cross-sectional area.
c) Increase in length of the magnetic path.
d) Decrease in relative permeability of the magnetic material of the circuit.

37. A ring-shaped coil with fixed number of turns of it carries a current of certain magnitude. If an iron core is threaded into the coil without any change in coil dimensions, the magnetic induction density will Increase
b) Reduce
c) remain unaffected
d) unpredictable

38. The ratio of total flux (flux in the iron path) to useful flux (flux in the air gap) is called

a) utilization factor
b) fringing factor leakage factor
d) depreciation factor

39. According to Faraday’s law of electromagnetic induction, an emf is induced in a conductor whenever it

a) lies in a magnetic field.
b) Lies perpendicular to the magnetic field. Cuts the magnetic flux.
d) Moves parallel to the direction of magnetic field.

40. “In all cases of electromagnetic induction, an induced voltage will cause a current to flow in a closed circuit in such a direction that the magnetic field which is caused by that current will oppose the change that produces the current”, is the original statement of Lenz’s law.
b) Faraday’s law of magnetic induction.
c) Fleming’s law of induction.
d) Ampere’s law.

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