ICS Part 2 Physics Chapter 15 Short Questions Preparation

Question # 1

What is back motor effect in generators?

Ans 1: Back motor effect is the opposing torque produced due to the induced emf in the coil.When coil rotated a current is drawn through the coil.The magnetic field exerts two equal and opposite forces on left and right side of the current carrying coil,These forces are such that they produce a counter torque that oppose the rotational motion of the coil.This effect is known as back motor effect in generators.

Question # 2

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 # 3

State Faraday's law of electromagnetic induction.

Ans 1: It states that
"The average emf induced in a conducting coil of N loops is equal to the negative of the rate at which the magnetic flux through the coil is changing with time".

Question # 4

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.

Ans 1: If the secondary circuit is open then output power will be zero,Because output power is always slightly smaller than the input power,therefore a very small value of current is being drawn by a primary coil of transformer from AC units,

Question # 5

If area of the loop and magnetic field both are changing and still have no induced emf.Explain why?

Ans 1: If the plane of the loop is kept parallel to the direction of the magnetic field,magnetic field through the coil will be zero,no emf will be induced in the loop either by changing its are or by changing the magentic field.

Question # 6

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

Ans 1: The split rings are two halves of a ring that acts as commutator.When the current in the coil is zero and is about to change direction,the split ring also changes the contacts with the carbon brushes,Therefore the output remains the same direction although the current is not constantan magnitude.

Question # 7

Define mutual induction.

Ans 1: The phenomena in which the changing current in one coil induces an emd in another coil is called the mutual induction.

Question # 8

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.

Question # 9

Name four methods to produce induce emf.

Ans 1: An induce emf is produced in the loop if the magnetic flux through it changes.The methods to produce induced emf are:
1. A bar magnet is moved towards the coil.
2. By changing the area of the coil in a constant magnetic field.
3. A coil of constant area is rotated in a constant magnetic field,
4. The coil is placed in the magnetic field of an electromagnet.

Question # 10

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

Ans 1: No,it is not possible.Because if it possible,it will be a self operating system without getting energy from some external source and this is against the law of conservation of energy.

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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 back motor effect in generators?

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

State Faraday's law of electromagnetic induction.

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.

If area of the loop and magnetic field both are changing and still have no induced emf.Explain why?

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

Define mutual induction.

What is back emf in motors?

Name four methods to produce induce emf.

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

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 back motor effect in generators?

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

State Faraday's law of electromagnetic induction.

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.

If area of the loop and magnetic field both are changing and still have no induced emf.Explain why?

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

Define mutual induction.

What is back emf in motors?

Name four methods to produce induce emf.

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

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

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

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

Define self induction and mutual induction.

What is back emf in motors?

What is meant by back emf?Write its SI units.

Does the induced current depend on the resistance of the circuit?

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

What is mean by commutator in D.C generator?

What is the working principle of transformer?Explain

Define electromagnetic induction.

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

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

Define mutual induction.

Define self induction and also write its SI units.

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

What is back emf in motors?

What happen to the current of a circuit if a load resistance of the circuit is much less than the power transferred?

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

Distinguished between AC generator and transformer.

Define motional emf and write its formula.

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

Can DC motor be turned into DC generator?What changes are required to be done?

Can a transformer be used with D.C? Explain

A suspended magnet is oscillating freely in the horizontal plane.The oscillation are strongly damped when a metal plate is placed under,The magnet.Explain why its occurs.

Name four methods to produce induce emf.

What is DC motor?Write its principle.

What happen to the current of a circuit if a load resistance of the circuit is much less than the power transferred?

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

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

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.

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

ICS Part 2 Physics Chapter 15 Short Questions Preparation

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