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Q1. | Air-core coils are practically free from |

A. | hysteresis losses [Wrong Answer] |

B. | eddy current losses [Wrong Answer] |

C. | both (a) and (b) [Correct Answer] |

D. | none of the above [Wrong Answer] |

View Answer
Explanation:-
Answer : CDiscuss it below :Md Said on 2016-11-16 04:31:45F=bil sin@ = .67×50×3×sin90= 100.5N !! OOPS Login [Click here] is required to post your answer/resultHelp other students, write article, leave your comments |

**Also Read Similar Questions Below :**

⇒ Current changing from 8 A to 12 A in one second induced 20 volts in a coil. The value of inductance is

5 mH

10 mH

5 H

10 H

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

Air core

Laminated iron core

Iron core

Powdered iron core

⇒ Air-core coils are practically free from

hysteresis losses

eddy current losses

both (a) and (b)

none of the above

⇒ 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

⇒ 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

⇒ 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

⇒ 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

⇒ 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

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

Faraday

Lenz

Newton

Coulomb

⇒ 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

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

unaffected

doubled

halved

quadrupled

⇒ 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

⇒ 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

⇒ Which of the following is unit of inductance?

Ohm

Henry

Ampere turns

Webers/metre

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

induced current

charge

enery

induced e.m.f.

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

300 µH

600 µH

150 µH

75 µH

⇒ In case of an inductance, current is proportional to

voltage across the inductance

magnetic field

both (a) and (b)

neither (a) nor (b)

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

Inductance

Condenser

Variable resistor

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⇒ 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

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

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Lenz's law

Fleming's right hand rule

Kirchhoffs voltage law

⇒ 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

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decrease

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

Henry

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Volt second per ampere

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⇒ An averaVoltage of 10 V is induced in a 250 turns solenoid as a result of a change in flux which occurs in 0.5 second. The total flux change is

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2 Wb

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⇒ 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

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moves parallel to the direction of the magnetic field

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

Capacitance

Inductance

Resistance

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⇒ The co-efficient of coupling between two air core coils depends on

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mutual inductance between two coils only

mutual inductance and self inductance of two coils

none of the above

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

Resistance only

Inductance only

Capacitance only

Inductance and capacitance

⇒ 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