ICS Part 2 Physics Chapter 15 Short Questions Preparation

Question # 1

What is electromagnet?Mention two practical example of electromagnet.

Ans 1: When a specimen of iron is placed inside a current carrying solenoid,it becomes and electromagnet.Examples are
1. Transformers
2. Motors

Question # 2

In a transformer there is no transfer of charge from the primary to the secondary.How is then the power transferred?

Ans 1: The power will be transferred because the two coils of transformer are magnetically linked i.e, the change of flux through one coil is linked with the other coil.

Question # 3

How does Lenz's law explain law of conservation of energy phenomena of electromagnetism induction?

Ans 1: When a rod is moving in the magnetic field towards right,an induced current flows through the loop in anticlockwise direction,Since current carrying rod experience a magnetic force opposite to that velociety.An external force equal in magnitude and opposite in direction must be applied to keep the rod moving with constant velocity.This dragging force provides the energy for the induced current to flow,This energy is the source of induced current.Thus electromagnetic induction is exactly according to law of conservation of energy.

Question # 4

Name the factor upon which the self inductance depends.

Ans 1: It depends upon induced emd and time rate of change of current in the coil.It also depend upon the number of turns of the coil,its area of cross section and the core material.

Question # 5

State the Lenz's law and define Henry.

Ans 1: Lenz's Law: It states that the direction of induced current is always so as to opposite the change which cause the current.
Henry: If the current in the primary is changing at the rate of one ampere per second and the emf induced across the ends of the secondary coil is one volt then the mutual inductance is called one henry.

Question # 6

When the primary of a transformer is connected to AC mains the current in it increase when secondary circuit is closed.Explain why?

Ans 1: When the secondary circuit is closed the output power increase.To produce the power ,transformer will draw large current from the A.C mains to increase its primary power.

Question # 7

What changes are required to turn the D.C motor into D.C generators?

Ans 1:
1. In order to convert DC motor into DC generator the magnetic field must be supplied by the permanent magnet and not by electromagnet.
2. An arrangement to rotate the coil armature should be provided and battery must be removed.

Question # 8

Define mutual inductance and write at least two factors at which it depends.

Ans 1: The ratio of average emf induced in the secondary to the time rate of changing current in the primary is called mutual inductance.
It depends upon numbers of turn of the coil,area of cross section of the coil closeness of coil and nature of the core materials.

Question # 9

A glass rod of "L"Length is moving perpendicular to the applied magnetic field P with velociety v.Explain briefly about the induced emf in it.

Ans 1: Induced emf is zero.As glass rod is insulator and there are no free electrons to be shifted from one extreme to the other.Therefore there will be no effect of perpendicular magnetic field.The induced emf is only produced by moving a conductor across the magnetic field.

Question # 10

What is back emf in motors?

Ans 1: When to coil motor rotates across the magnetic field by the applied potential difference V,an emf is induced in it.The induced emf is in such a direction that opposes the emf running motor.Due to this reasons,the induced emf is called back emf of the motor.The magnitude of the back emf increase with the speed of motor.

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ICS Part 2 Physics Chapter 15 Short Questions Preparation

12th Class PhysicsShort Questions Preparation

12th Class Physics Chapter Wise Preparation

Online Short Questions For Chapter 4 "ICS Part 2 Physics Chapter 15 Short Questions Preparation "

Physics - ICS Part 2 Physics Chapter 15 Short Questions Preparation

What is electromagnet?Mention two practical example of electromagnet.

In a transformer there is no transfer of charge from the primary to the secondary.How is then the power transferred?

How does Lenz's law explain law of conservation of energy phenomena of electromagnetism induction?

Name the factor upon which the self inductance depends.

State the Lenz's law and define Henry.

When the primary of a transformer is connected to AC mains the current in it increase when secondary circuit is closed.Explain why?

What changes are required to turn the D.C motor into D.C generators?

Define mutual inductance and write at least two factors at which it depends.

A glass rod of "L"Length is moving perpendicular to the applied magnetic field P with velociety v.Explain briefly about the induced emf in it.

What is back emf in motors?

Prepare Complete Set Wise Questions For Chapter 4 "ICS Part 2 Physics Chapter 15 Short Questions Preparation "

Set 1

Set 2

Set 3

Set 4

ICS Part 2 Physics Chapter 15 Short Questions Preparation - Set 1

What is electromagnet?Mention two practical example of electromagnet.

In a transformer there is no transfer of charge from the primary to the secondary.How is then the power transferred?

How does Lenz's law explain law of conservation of energy phenomena of electromagnetism induction?

Name the factor upon which the self inductance depends.

State the Lenz's law and define Henry.

When the primary of a transformer is connected to AC mains the current in it increase when secondary circuit is closed.Explain why?

What changes are required to turn the D.C motor into D.C generators?

Define mutual inductance and write at least two factors at which it depends.

A glass rod of "L"Length is moving perpendicular to the applied magnetic field P with velociety v.Explain briefly about the induced emf in it.

What is back emf in motors?

ICS Part 2 Physics Chapter 15 Short Questions Preparation - Set 2

Define self induction and mutual induction.

In a certain region the earth's magnetic field points vertically down,When a plane flies due north,which wing tip is positively charged?

Can an electric motor be used to derive and electric generator with output from the generator being used to operate the motor?

Define mutual inductance and write at least two factors at which it depends.

Distinguished between AC generator and transformer.

When the primary of a transformer is connected to A.C mains,the current it is very small if the secondary circuit is open.Explain.

State the Lenz's law and define Henry.

Why is split ring is used in DC generators in place of slips rings?

Write two similarities and two difference between motor and generator.

Name the factor upon which the self inductance depends.

ICS Part 2 Physics Chapter 15 Short Questions Preparation - Set 3

Can an electron at rest be set in motion with magnet?Explain

What is the working principle of transformer?Explain

What is electromagnet?Mention two practical example of electromagnet.

Define induced emf and induced current.

Define mutual inductance and write at least two factors at which it depends.

What is back emf in motors?

Define motional emf and write its formula.

Can a transformer be used with D.C? Explain

What changes are required to turn the D.C motors into a D.C generators?

Is it possible to change both the area of the loop and magnetic field passing through the loop and still have bo induced emf in the loop?Explain briefly.

ICS Part 2 Physics Chapter 15 Short Questions Preparation - Set 4

Does the induced emf always act to decrease the magnetic flux through a circuit?

Define mutual induction.

What is the working principle of transformer?Explain

What is mean by commutator in D.C generator?

What changes are required to turn the D.C motors into a D.C generators?

Define self induction and mutual induction.

Distinguished between AC generator and transformer.

Define mutual inductance and write at least two factors at which it depends.

Can an electric motor be used to derive and electric generator with output from the generator being used to operate the motor?

Define electromagnetic induction.

ICS Part 2 Physics Chapter 15 Short Questions Preparation

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