Back emf refers to the

Question

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

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Comment

Ohm's law can be used only to a _____ circuit or component.

A. Unilateral

B. Exponential

C. Trivalent

D. Linear

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A magnetic circuit carries a flux iin the iron part and a fluxgin the air gap. What is the leakage coefficient?

A. i/g

B. i × g

C. g/ i

D. i + g

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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

Discuss this answer

Steel is hard to magnetize because of its

A. Low permeability

B. High permeability

C. High density

D. High retentivity

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The straight line passing through the two poles of magnet is called

A. Real axis

B. Cartesian axis

C. Magnetic axis

D. Imaginary axis

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Electrons at the outer shell are called

A. Outer shell electrons

B. Inner shell electrons

C. Semiconductor electrons

D. Valence electrons

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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

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Temporary magnets are commonly employed in

A. electric instruments

B. motors

C. moving coils loudspeakers

D. magnetos

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If the magnetic material is located within a coil through which alternating current (60 Hz frequency) flowsa then __________ hysteresis loops will be formed

A.

B.

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A law establishing the fact that the algebraic su of the rises and drops of the mmf around a closed loop of a magnetic circuit is equal to zero.

A. Kirchhoff's circuital law

B. Maxwell's circuital law

C. Ampere's circuital law

D. Coulomb's circuital law

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Materials whose permeabilities are slightly greater than that of free space

A. Paramagnetic

B. Non- magnetic

C. Ferromagnetic

D. Diamagnetic

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The greater percentage of materials is _________.

A. diamagnetic

B. paramagnetic

C. ferromagnetic

D. non-magnetic

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What is the SI unit of reluctance?

A. At

B. At/m

C. N/Wb

D. At/Wb

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An atom or a group of atoms that carries a net electric charge.

A. Positive ion

B. Negative ion

C. Ion

D. Electron

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Permanent magnets can be found in

A. electric bells

B. earphones

C. relays

D. dy namic loudspeakers

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The relative permeability of a magnetic material is 10^5. What is its permeability?

A. 4 × 10^5 H/m

B. 4 × 10^-12 H/m

C. 4× 10^-2 H/m

D. 4 × 10^7H/m

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Lenz' law states that the direction of the induced emf and hence current

A. Is determined by the rate of current flux

B. Is found by the right hand rule

C. Is found by the left hand rule

D. Always opposes the cause producing it

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A negatively charge body has

A. deficit of electrons

B. excess of protons

C. excess of electrons

D. deficit of neutrons

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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

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If the value of 0 a conductor is 1/234 per oCa then the value of 18is

A. 1/218 per oC

B. 1/252 peroC

C. 1/272 per oC

D. 1/273 per oC

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What type of bond is formed when there exists some form of collective interactions between the (negatively charged) electrons and (positively charged) nuclei in a solid?

A. Ionic

B. Covalent

C. Metallic

D. Van der Waals

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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

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The magnetic field of a bar magnet most closely resembles the magnetic field of

A. a horseshoe magnet

B. a straight current- carrying wire

C. a stream of electrons moving parallel to one another

D. a current- carrying wire loop

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An alloy of 40 percent iron and 60 percent nickel.

A. Alnico

B. Permalloy

C. Hipernik

D. Manganin

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The electric flux density is a ________ quantity.

A. phasor

B. vector

C. scalar

D. variable

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A magnetic field is

A. The current flow through space around a permanent magnet

B. The force set up when current flows through a conductor

C. The force that drives current through a resistor

D. The force between the plates of a charged capacitor

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Flux linkages equals

A. Flux times area of core

B. Flux times number of turns times area of core

C. Flux times number of turns times length of core

D. Flux times number of turns

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Referred to as the specific reluctance of a material

A. Resistivity

B. Reluctivity

C. Conductivity

D. Permeability

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Germanium atom has protons and electrons.

A. 32, 32

B. 32, 42

C. 42, 32

D. 34, 34

Discuss this answer

The resistivity of a conductor ___________ with an increase in temperature.

A. increases

B. decreases

C. remains the same

D. becomes zero

Discuss this answer

Accepted Answer

D. Voltage opposing the applied emf

Back emf refers to the

Correct Answer :

Show all Electricity Fundamentals MCQ

Related Questions

Ohm's law can be used only to a _____ circuit or component.

A magnetic circuit carries a flux iin the iron part and a fluxgin the air gap. What is the leakage coefficient?

The energy stored in an electrostatic field or electromagnetic field is called

Steel is hard to magnetize because of its

The straight line passing through the two poles of magnet is called

Electrons at the outer shell are called

Which of the following is used by temporary magnets as the magnetic material?

Temporary magnets are commonly employed in

If the magnetic material is located within a coil through which alternating current (60 Hz frequency) flowsa then __________ hysteresis loops will be formed

A law establishing the fact that the algebraic su of the rises and drops of the mmf around a closed loop of a magnetic circuit is equal to zero.

Materials whose permeabilities are slightly greater than that of free space

The greater percentage of materials is _________.

What is the SI unit of reluctance?

An atom or a group of atoms that carries a net electric charge.

Permanent magnets can be found in

The relative permeability of a magnetic material is 10^5. What is its permeability?

Lenz' law states that the direction of the induced emf and hence current

A negatively charge body has

A one cubic cm of copper has how many free electrons at room temperature?

If the value of 0 a conductor is 1/234 per oCa then the value of 18is

What type of bond is formed when there exists some form of collective interactions between the (negatively charged) electrons and (positively charged) nuclei in a solid?

A commercial alloy of aluminum nickela and iron with cobalta copper and titanium added to produce about 12 grades.

The magnetic field of a bar magnet most closely resembles the magnetic field of

An alloy of 40 percent iron and 60 percent nickel.

The electric flux density is a ________ quantity.

A magnetic field is

Flux linkages equals

Referred to as the specific reluctance of a material

Germanium atom has protons and electrons.

The resistivity of a conductor ___________ with an increase in temperature.

Also checkout

Back emf refers to the

Correct Answer :

Show all Electricity Fundamentals MCQ

Related Questions

Ohm's law can be used only to a _____ circuit or component.

A magnetic circuit carries a flux iin the iron part and a fluxgin the air gap. What is the leakage coefficient?

The energy stored in an electrostatic field or electromagnetic field is called

Steel is hard to magnetize because of its

The straight line passing through the two poles of magnet is called

Electrons at the outer shell are called

Which of the following is used by temporary magnets as the magnetic material?

Temporary magnets are commonly employed in

If the magnetic material is located within a coil through which alternating current (60 Hz frequency) flowsa then __________ hysteresis loops will be formed

A law establishing the fact that the algebraic su of the rises and drops of the mmf around a closed loop of a magnetic circuit is equal to zero.

Materials whose permeabilities are slightly greater than that of free space

The greater percentage of materials is _________.

What is the SI unit of reluctance?

An atom or a group of atoms that carries a net electric charge.

Permanent magnets can be found in

The relative permeability of a magnetic material is 10^5. What is its permeability?

Lenz' law states that the direction of the induced emf and hence current

A negatively charge body has

A one cubic cm of copper has how many free electrons at room temperature?

If the value of 0 a conductor is 1/234 per oCa then the value of 18is

What type of bond is formed when there exists some form of collective interactions between the (negatively charged) electrons and (positively charged) nuclei in a solid?

A commercial alloy of aluminum nickela and iron with cobalta copper and titanium added to produce about 12 grades.

The magnetic field of a bar magnet most closely resembles the magnetic field of

An alloy of 40 percent iron and 60 percent nickel.

The electric flux density is a ________ quantity.

A magnetic field is

Flux linkages equals

Referred to as the specific reluctance of a material

Germanium atom has ______ protons and ______ electrons.

The resistivity of a conductor ___________ with an increase in temperature.

Also checkout

Germanium atom has protons and electrons.