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Q1. | A laminated iron core has reduced eddy-current losses because |

A. | more wire can he used with less D.C. resistance in coil [Wrong Answer] |

B. | the laminations are insulated from each other [Correct Answer] |

C. | the magnetic flux is concentrated in the air gap of the core [Wrong Answer] |

D. | the laminations are stacked vertically [Wrong Answer] |

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Explanation:-
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**Also Read Similar Questions Below :**

⇒ Which of the following statements is cotrect ?

The inductance of the coil carrying a constant D.C. current will change the current into pulses

The inductance of the coil carrying a constant D.C. current will increase the current

The inductance of the coil carrying a constant D.C. current will not affect the current

The inductance of the coil carrying a constant D.C. current will decrease the current

⇒ A conductor carries 125 amperes of current under 60° to a magnetic field of 1.1 tesla. The force on the conductor will be nearly

50 N

120 N

240 N

480 N

⇒ An open coil has

zero resistance and inductance

infinite resistance and zero inductance

infinite resistance and normal inductance

zero resistance and high inductance

⇒ For a purely inductive circuit which of the following is true ?

Apparent power is zero

Relative power is zero

Actual power of the circuit is zero

Any capacitance even if present in the circuit will not be charged

⇒ As per Faraday's laws of electromagnetic induction, an e.m.f. is induced in a conductor whenever it

lies perpendicular to the magnetic flux

lies in a magnetic field

cuts magnetic flux

moves parallel to the direction of the magnetic field

⇒ In an iron cored coil the iron core is removed so that the coil becomes an air cored coil. The inductance of the coil will

increase

decrease

remain the same

initially increase and then decrease

⇒ Mutually inductance between two magnetically-coupled coils depends on

permeability of the core

the number of their turns

cross-sectional area of their common core

all of the above

⇒ Two 300 µH coils in series without mutual coupling have a total inductance of

300 µH

600 µH

150 µH

75 µH

⇒ A coil with negligible resistance has 50 V across it with 10 mA. The inductive reactance is

50 ohms

500 ohms

1000 ohms

5000 ohms

⇒ Two coils have self-inductances of 10 H and 2 H, the mutual inductance being zero. If the two coils are connected in series, the total inductance will be

6 H

8 H

12 H

24 H

⇒ A 500 turns solenoid develops an average induced voltage of 60 V. Over what time interval must a flux change of 0.06 Wb occur to produce such a voltage?

0.01 s

0.1 s

0.5 s

5 s

⇒ A laminated iron core has reduced eddy-current losses because

more wire can he used with less D.C. resistance in coil

the laminations are insulated from each other

the magnetic flux is concentrated in the air gap of the core

the laminations are stacked vertically

⇒ The magnitude of the induced e.m.f. in a conductor depends on the

flux density of the magnetic field

amount of flux cut

amount of flux linkages

rate of change of flux-linkages

⇒ The direction of induced e.m.f. can be found by

Laplace's law

Lenz's law

Fleming's right hand rule

Kirchhoffs voltage law

⇒ Ifcurrentin a conductor increases then according to Lenz's law self-induced voltage will

aid the increasing current

tend to decrease the amount of current

produce current opposite to the increasing current

aid tite applied voltage

⇒ The inductance df a coil will increase under all the following conditions except

when more length for the same number of turns is provided

when the number of turns of the coil increase

when more area for each turn is provided

when permeability of the core increases

⇒ A coil induces 350 mV when the current changes at the rate of 1 A/s. The value of inductance is

3500 mH

350 mH

250 mH

150 mH

⇒ In case of an inductance, current is proportional to

voltage across the inductance

magnetic field

both (a) and (b)

neither (a) nor (b)

⇒ A 200 turn coil has an inductance of 12 mH. If the number of turns is increased to 400 turns, all other quantities (area, length etc.) remaining the same, the inductance will be

6 mH

14 mH

24 mH

48 mH

⇒ Which of the following circuit elements will oppose the change in circuit current?

Capacitance

Inductance

Resistance

All of the above

⇒ Which of the following is not a unit of inductance?

Henry

Coulomb/volt ampere

Volt second per ampere

All of the above

⇒ The core of a coil has a length of 200 mm. The inductance of coil is 6 mH. If the core length is doubled, all other quantities, remaining the same, the inductance will be

3 mH

12 mH

24 mH

48 mH

⇒ Which circuit element(s) will oppose the change in circuit current?

Resistance only

Inductance only

Capacitance only

Inductance and capacitance

⇒ Air-core coils are practically free from

hysteresis losses

eddy current losses

both (a) and (b)

none of the above

⇒ The property of coil by which a counter e.m.f. is induced in it when the current through the coil chatiges is known as

self-inductance

mutual inductance

series aiding inductace

capacitance

⇒ Lenz's law is a consecluence of the law of conservation of

induced current

charge

enery

induced e.m.f.

⇒ The law that the induced e.m.f. and current always oppose the cause producing them is due to

Faraday

Lenz

Newton

Coulomb

⇒ Find the force acting on a conductor 3m long carrying a current of 50 amperes at right angles to a magnetic field having a flux density of 0.67 tesla.

100 N

400 N

600 N

1000 N

⇒ An e.m.f. of 16 volts is induced in a coil of inductance 4 H. The rate of change of current must be

64 A/s

32 A/s

16 A/s

4 A/s

⇒ Both the number of turns and the core length of an inductive coil are doubled. Its self-inductance will be

unaffected

doubled

halved

quadrupled