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Q1. | Which of the following inductor will have the least eddy current losses? |

A. | Air core [Correct Answer] |

B. | Laminated iron core [Wrong Answer] |

C. | Iron core [Wrong Answer] |

D. | Powdered iron core [Wrong Answer] |

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

⇒ A coil is wound on iron core which carries current I. The self induced voltage in the coil is not affected by

variation in coil current

variation in voltage to the coil

change of number of turns of coil

the resistance of magnetic path

⇒ 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

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

50 ohms

500 ohms

1000 ohms

5000 ohms

⇒ 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

⇒ In case all the flux from the current in coil 1 links with coil 2, the co-efficient of coupling will be

2.0

1.0

0.5

zero

⇒ 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

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

Henry

Coulomb/volt ampere

Volt second per ampere

All of the above

⇒ Higher the self-inductance of a coil,

lesser its weher-turns

lower the e.m.f. induced

greater the flux produced by it

longer the dela' in establishing steady current through it

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

Resistance only

Inductance only

Capacitance only

Inductance and capacitance

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

300 µH

600 µH

150 µH

75 µH

⇒ 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

⇒ 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

⇒ Two coils have inductances of 8 mH and 18 mH and a co-efficient of coupling of 0.5. If the two coils are connected in series aiding, the total inductance will be

32 mH

38 mH

40 mH

48 mH

⇒ Which of the following is unit of inductance?

Ohm

Henry

Ampere turns

Webers/metre

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

unaffected

doubled

halved

quadrupled

⇒ In case of an inductance, current is proportional to

voltage across the inductance

magnetic field

both (a) and (b)

neither (a) nor (b)

⇒ 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

⇒ The co-efficient of self-inductance for a coil is given as

NI/Φ

NΦ/I

NI

^{2}/Φ

NΦ/I

^{2}

⇒ 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

⇒ 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

⇒ Which of the following circuit element stores energy in the electromagnetic field?

Inductance

Condenser

Variable resistor

Resistance

⇒ 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

⇒ The self inductances of two coils are 8 mH and 18 mH If the co-efficients of coupling is 0.5, the mutual inductance of the coils is

4 mH

5 mH

6 mH

12 mH

⇒ 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

⇒ Which of the following inductor will have the least eddy current losses?

Air core

Laminated iron core

Iron core

Powdered iron core

⇒ 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

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

Capacitance

Inductance

Resistance

All of the above

⇒ A crack in the magnetic path of an inductor will result in

unchanged inductance

increased inductance

zero inductance

reduced inductance

⇒ 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