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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 :**

⇒ An open coil has

zero resistance and inductance

infinite resistance and zero inductance

infinite resistance and normal inductance

zero resistance and high inductance

⇒ 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

⇒ 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

20 Wb

2 Wb

0.2 Wb

0.02 Wb

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

unchanged inductance

increased inductance

zero inductance

reduced inductance

⇒ Air-core coils are practically free from

hysteresis losses

eddy current losses

both (a) and (b)

none of the above

⇒ 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

⇒ 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 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

⇒ 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

⇒ 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

⇒ 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

⇒ 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

⇒ 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

⇒ 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

⇒ 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

⇒ A conductor 2 metres long moves at right angles to a magnetic field of flux densit 1 tesla with a velocity of 12.5 m/s. The induced e.m.f. in the conductor will be

10 V

15 V

25 V

50 V

⇒ 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

⇒ 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

⇒ 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

⇒ 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

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

Faraday

Lenz

Newton

Coulomb

⇒ 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

⇒ In case of an inductance, current is proportional to

voltage across the inductance

magnetic field

both (a) and (b)

neither (a) nor (b)

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

self-inductance of two coils only

mutual inductance between two coils only

mutual inductance and self inductance of two coils

none of the above

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

Air core

Laminated iron core

Iron core

Powdered iron core

⇒ 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

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

induced current

charge

enery

induced e.m.f.

⇒ 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