The magnetic reluctance of a material

by

1 Answer

Answer :

The magnetic reluctance of a material decreases with increasing cross-sectional area of the material.

by

Related questions

The resistance in a magnetic material is called as a) Capacitance b) Inductance c) Reluctance d) Magnetic resistance

Description : The resistance in a magnetic material is called as a) Capacitance b) Inductance c) Reluctance d) Magnetic resistance

Last Answer : c) Reluctance

A material which is slightly repelled by a magnetic field is known as

Last Answer : A material which is slightly repelled by a magnetic field is known as diamagnetic material.

The function of the commutator in a DC motor is to ________. A. reverse the flow of current through the armature B. reverse the flow of current in the field poles C. reduce the reluctance of the magnetic path through the motor D. shift the neutral running plane of the brushes to prevent sparking

Description : The function of the commutator in a DC motor is to ________. A. reverse the flow of current through the armature B. reverse the flow of current in the field poles C. reduce the reluctance of the magnetic path through the motor D. shift the neutral running plane of the brushes to prevent sparking

Last Answer : Answer: A

The opposition to the establishment of magnetic lines of force in a magnetic circuit is called the circuit's _______. A. resistance B. reluctance C. impedance D. inductance

Description : The opposition to the establishment of magnetic lines of force in a magnetic circuit is called the circuit's _______. A. resistance B. reluctance C. impedance D. inductance

Last Answer : Answer: B

68 The path of a magnetic flux in a transformer should have A. High resistance B. High reluctance C. Low resistance D. Low reluctance

Description : 68 The path of a magnetic flux in a transformer should have A. High resistance B. High reluctance C. Low resistance D. Low reluctance

Last Answer : D. Low reluctance

43 The purpose of providing an iron core in a transformer is to A.Provide support to windings B. Reduce hysteresis loss C. decrease the reluctance of the magnetic path D. reduce eddy current losses

Description : 43 The purpose of providing an iron core in a transformer is to A.Provide support to windings B. Reduce hysteresis loss C. decrease the reluctance of the magnetic path D. reduce eddy current losses

Last Answer : C. Decrease the reluctance of the magnetic path

Define reluctance and permeance with respect to magnetic circuit.

Description : Define reluctance and permeance with respect to magnetic circuit.

Last Answer : Reluctance: The opposition offered by magnetic circuit to establish magnetic flux in it, is called as “Reluctance”.  Permeance: It is the reciprocal of reluctance and implies the magnetic core’s readiness with which magnetic flux is developed. 

Define the following terms: i) Magnetic flux density, ii) Reluctance, iii) Magneto-motive force, iv) Permeance.

Description : Define the following terms: i) Magnetic flux density, ii) Reluctance, iii) Magneto-motive force, iv) Permeance.

Last Answer : (i) Magnetic flux density (B): It is the magnetic flux per unit area measured at right angles to the flux path. (Its unit is weber/m2 or tesla).  (ii) Reluctance: It is the ... flux to set up through it and it is reciprocal of reluctance. Permeance = 1/ Reluctance. Unit: weber/ampere.

What is the SI unit for magnetic reluctance?

Description : What is the SI unit for magnetic reluctance? A) Ampere B) Ampere-turns per weber C) Henry D) None of these

Last Answer : What is the SI unit for magnetic reluctance? A) Ampere B) Ampere-turns per weber C) Henry D) None of these

Reluctance offered by the magnetic circuit depends upon _______.

Last Answer : Reluctance offered by the magnetic circuit depends upon nature of magnetic material, length of magnetic flux path, cross-sectional area of the material.

Calculate the reluctance of a material with length 2π x 10 -4 in air with area 0.5. a) 1 b) 10 c) 100 d) 1000

Description : Calculate the reluctance of a material with length 2π x 10 -4 in air with area 0.5. a) 1 b) 10 c) 100 d) 1000

Last Answer : d) 1000

Calculate the reluctance of the material with a mmf of 3.5 units and flux of 7units. a) 32.5 b) 10.5 c) 0.5 d) 2

Description : Calculate the reluctance of the material with a mmf of 3.5 units and flux of 7units. a) 32.5 b) 10.5 c) 0.5 d) 2

Last Answer : b) 10.5

The magnetic materials exhibit the property of magnetisation because of

Last Answer : The magnetic materials exhibit the property of magnetisation because of spin of nucleus.

The stray line of magnetic flux is defined as

Last Answer : The stray line of magnetic flux is defined as a line of magnetic flux which does not follow the designed path.

How does the magnetic compass needle behave in a magnetic field ?

Last Answer : It assures a position which follows a line of magnetic flux

The uniform magnetic field is

Last Answer : The uniform magnetic field is the field in which all lines of magnetic flux are parallel and equidistant.

Magnetic moment is a

Last Answer : Magnetic moment is a vector quantity.

A rectangular magnet of magnetic moment M is cut into two piece ...

Description : A rectangular magnet of magnetic moment M is cut into two piece of same length, the magnetic moment of each piece will be

Last Answer : A rectangular magnet of magnetic moment M is cut into two piece of same length, the magnetic moment of each piece will be M/2.

If a copper disc is rotated rapidly below a freely suspended magnetic...

Description : If a copper disc is rotated rapidly below a freely suspended magnetic needle, the magnetic needle shall start rotating with a velocity

Last Answer : If a copper disc is rotated rapidly below a freely suspended magnetic needle, the magnetic needle shall start rotating with a velocity less than that of disc and in the same direction.

When an iron piece is placed in a magnetic field

Last Answer :  When an iron piece is placed in a magnetic field the magnetic lines of force will bend away from their usual paths in order to pass through the piece.

The direction of magnetic lines of force is

Last Answer : The direction of magnetic lines of force is from north pole to south pole.

A magnetic field exists around

Last Answer : A magnetic field exists around moving charges.

______ is most commonly used for making magnetic recording tape.

Description : ______ is most commonly used for making magnetic recording tape.

Last Answer : Ferric oxide is most commonly used for making magnetic recording tape.

The retentivity (a property) of material is useful for the construction of

Last Answer : The retentivity (a property) of material is useful for the construction of permanent magnets.

The commonly used material for shielding or screening magnetism is

Last Answer : The commonly used material for shielding or screening magnetism is soft iron.

For a particular material the Hall coefficient was found to be zero. The material is

Last Answer : For a particular material, the Hall coefficient was found to be zero. The material is metal.

Surface resistance of an insulating material is reduced due to the

Last Answer : Surface resistance of an insulating material is reduced due to the smoky and dirty atmosphere, humidity in the atmosphere.

______ is an example of piezoelectric material.

Last Answer :  Quartz is an example of piezoelectric material.

Mercury as an electric contact material is?

Description : Mercury as an electric contact material is?

Last Answer : Mercury as an electric contact material is a metal liquid.

A highly conductive material must have?

Description : A highly conductive material must have?

Last Answer : A highly conductive material must have highest conductivity, lowest temperature co-efficient, good mechanical strength, good corrosion resistance, easy solderable and drawable quality.

What is reluctance in electronics?

Description : What is reluctance in electronics?

Last Answer : Need answer

What is the verb of reluctance?

Description : What is the verb of reluctance?

Last Answer : reluctant

The voltage output of an AC generator is accurately controlled by _____________. A. changing the sensitivity of the prime mover to large changes in voltage B. varying the reluctance of the air gap C. varying the DC exciter voltage D. shorting out part of the armature windings

Description : The voltage output of an AC generator is accurately controlled by _____________. A. changing the sensitivity of the prime mover to large changes in voltage B. varying the reluctance of the air gap C. varying the DC exciter voltage D. shorting out part of the armature windings

Last Answer : Answer: C

What is reluctance?

Description : What is reluctance? 

Last Answer : It is the property of a magnetic material, which opposes the establishment of magnetic flux in it, as in the case resistance in an electric circuit. 

The magnetism left in the iron after exciting field has been removed is known as (a) permeance (b) residual magnetism (c) susceptance (d) reluctance

Description : The magnetism left in the iron after exciting field has been removed is known as (a) permeance (b) residual magnetism (c) susceptance (d) reluctance

Last Answer : (b) residual magnetism

The range of wavelength values that a given photodiode will respond. ∙ A. spectral response ∙ B. permeance ∙ C. dark current ∙ D. reluctance

Description : The range of wavelength values that a given photodiode will respond. ∙ A. spectral response ∙ B. permeance ∙ C. dark current ∙ D. reluctance

Last Answer : A. spectral response

Which of the following methods may be adopted to reduce the effects of armature reaction ? (a) Increase in length of air gap at pole tips (b) Increasing reluctance of pole tips (c) Compensating windings (d) Interpoles (e) All of the above

Description : Which of the following methods may be adopted to reduce the effects of armature reaction ? (a) Increase in length of air gap at pole tips (b) Increasing reluctance of pole tips (c) Compensating windings (d) Interpoles (e) All of the above

Last Answer : (e) All of the above

The slot leakage can be calculated by making which of the following assumptions ? (a) The current in the slot conductors is uniformly distributed over their cross-section (b) The leakage path is straight across the slot and around the iron at the bottom (c) The permanence of air paths is only considered. The reluctance of iron paths is assumed as zero (d) All of the above

Description : The slot leakage can be calculated by making which of the following assumptions ? (a) The current in the slot conductors is uniformly distributed over their cross-section (b) The leakage path is straight ... is only considered. The reluctance of iron paths is assumed as zero (d) All of the above

Last Answer : (d) All of the above

Define (i) Permeability (ii) Reluctance.

Description : Define (i) Permeability (ii) Reluctance.

Last Answer : Permeability: The capability of the magnetic material to conduct the magnetic flux is known as permeability (OR) It is defined as ratio of magnetic flux density B in a medium to the magnetic flux intensity ... as the property of a material due to which it opposes the creation of magnetic flux in it.

Compare variable reluctance and permanent magnet motors.

Description : Compare variable reluctance and permanent magnet motors.

Last Answer : Variable reluctance Motor  Permanent magnet motors   The rotor is not magnetised The rotor is magnetised  High torque to inertia ratio  Low torque to inertia ratio  ... rotor has salient pole construction The rotor has mostly smooth cylindrical type of construction. 

THE UNIT OF RELUCTANCE IS

Description : THE UNIT OF RELUCTANCE IS

Last Answer : The si unit of reluctance is Ampere-turn/weber

Define : i) MMF ii) Reluctance iii) Fringing iv) Leakage flux

Description : Define : i) MMF ii) Reluctance iii) Fringing iv) Leakage flux

Last Answer : i) MMF:  It is the force that drives magnetic flux through magnetic circuit. It is measured in amp-turns.  ii) Reluctance (s) :-  Reluctance is the property of the substance ... through the magnetic circuit, leaks through the air surrounding the core. This flux is called as leakage flux.

Define reluctance and give its unit.

Description : Define reluctance and give its unit.

Last Answer : Reluctance is the resistance offered the material to the passage of magnetic flux through it and corresponds to resistance in the electric circuit it is denoted by (s) And it's unit is amper per weber (A/Wb)

A three-phase, three-stack, variable reluctance step motor has 20 poles on each rotor and stator stack.

Description : A three-phase, three-stack, variable reluctance step motor has 20 poles on each rotor and stator stack. The step angle of this step motor is  (A) 3o (B) 6o (C) 9o (D) 18o

Last Answer : A three-phase, three-stack, variable reluctance step motor has 20 poles on each rotor and stator stack. The step angle of this step motor is  6o

The maximum reluctance power of a salient-pole synchronous motor having direct-axis reactance, 1.0 pu and

Description : The maximum reluctance power of a salient-pole synchronous motor having direct-axis reactance, 1.0 pu and quadrature-axis reactance, 0.5 pu, and input voltage, 1.0 pu is (A) 0.25 pu (B) 0.5 pu (C) 1.0 pu (D) 1.5 pu

Last Answer : The maximum reluctance power of a salient-pole synchronous motor having direct-axis reactance, 1.0 pu and quadrature-axis reactance, 0.5 pu, and input voltage, 1.0 pu is 0.5 pu

Reciprocal of reluctance is?

Description : Reciprocal of reluctance is?

Last Answer : Reciprocal of reluctance is permeance.

In case of a reluctance motor, when the load is increased so that it cannot maintain synchronous speed the motor will?

Last Answer : In case of a reluctance motor, when the load is increased so that it cannot maintain synchronous speed the motor will run as induction motor.

Reluctance motor

Description : Reluctance motor

Last Answer : Reluctance motor Reluctance is opposition to magnetic flux. Reluctance is analogous to electric resistance. Reluctance motor does not have any winding on rotor. Rotor consists of  ... for rotation of rotor is generated through magnetic reluctance so it called reluctance motor.

Ferromagnets

Description : Ferromagnets

Last Answer : Ferromagnets Only certain materials, such as iron, cobalt, nickel, and gadolinium, exhibit strong magnetic effects. Such materials are called ferromagnetic, after the Latin word for iron, ... licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

The attraction capacity of electromagnet will increase if the

Last Answer : Atrraction  capacity  will  increase  if  supply  current  is  increased.