Question # 1

The direction of induced current is always so as to oppose the cause which produces it. This is

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Lenz's law

Ampere's law

Faraday's law

Coulomb's law

None of these

Eddy current is produced when:

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A metal is kept in varying magnetic field

A metal is kept in steady magnetic field

A circular coil is placed in a steady magnetic field

A current is passed through a circular coil

Referring to above figure, current in the coil P grows from zero to its maximum value

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At the instant the switch is closed

At the instant the switch is opened

When switch is kept open

All of above

Neither of above

Self inducede e.m.f. is also called

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Motional e.m.f.

Thermistor

Electrostatic induction

Back e.m.f

The work is stored in the inductor as

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Electric potential energy

Elastic potential energy

Magnetic energy

Absolute potential energy

The change of magnetic flux through a circuit will produce

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Magnetic Field

Electric Field

emf

a.c

The magnitude of induced emf depends upon the

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Rate of decrease of magnetic field

Rate of change of magnetic field

Rate of increase of magnetic flux

Constancy of magnetic field

None of these

Instead of moving the coil towards a magnet, the magnet is moved towards the coil with the same speed. The galvanometer shows current

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Of same magnitude in the same direction

Of different magnitude in the same direction

Of same magnitude but in opposite direction

Of different magnitude in the opposite direction

None of these

The motional e.m.f depends upon the

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Length of a conductor

Strength of a magnet

Speed of the conductor

All of the above

A metal road of length 1m is moving at a speed of 1 ms^-1In a direction making angle of 30º with 0.5 Y magnetic field. The emf produced in the rod is:

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0.25 N

0.25 V

2.5 V

2.5 N

25 V

The induced current in a conductor depends upon:

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Resistance of the loop

Speed with which the conductor moves

Any of these

Both A and B

None of these

Step up transformer has a transformation ratio of 3:2. What is the voltage in secondary, if voltage in primary is 30V:

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45 V

15 V

90 V

300 V

An induced current can be produced by:

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Constant magnetic field

Changing magnetic field

Varying magnetic field

Constant electric field

None of these

Which of the following quantities remain constant in step up transformer?

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Current

Voltage

Power

Heat

Micheal Faraday and joseph Henry belong respectively to:

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USA and England

England and France

England and USA

USA and France

None of these

In the equilibrium state, the potential difference between two ends of the conductor moving across a magnetic field is called:

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Motion emf

Electrostatic emf

Induced emf

Both A and B

Both A and C

Which of the following is most suitable as the core of transformer

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Soft iron

Alinco

Steel

None of these

The device in which induced emf is statically induced emf is:

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Transformer

AC generator

Alternator

Dynamo

When a conductor moved with its length parallel to the lines of magnetic fled:

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An emf is induced across its ends

Emf induced is similar to that of a battery

Emf passes through the conductor

Both A and B

None of these

Referring to above figure, a changing current in coil P can be produced:

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At the instant the switch is closed

At the instant the switch is opened

With the help of rheostat

All of these

None of these

Referring to above figure, current in coil P falls from its maximum value to zero

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At the instant the switch is closed

At the instant the switch is opened

When switch is kept open

When switch is kept closed

None of these

When the conductor moved across a magnetic field:

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Emf induced is similar to that of a battery

Emf induced gives rise to induced current

An emf induced across its ends

All are correct

None of these

The practical application of the phenomenon of Mutual induction is

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Transformers

Generator

Motor

All of these

Split rings act as

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Vibrator

Resistor

Motor

Commulator

Referring to above figure, due to change in current in the coil P, the change in magnetic flux

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Is associated with coil P

Is associated with coil S

Causes and induced current in coil S

All of these

None of these

Michael Faraday and Joseph Henry belong respectively to

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USA and England

England and France

England and USA

USA and France

None of these

In a coil current change from 2 to 4 A in .05 s. If the average induced emf is 8V then coefficient of self-inductance is:

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0.2 henry

0.1 henry

0.8 henry

0.04 henry

The phenomenon of generation of induced emf is called:

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Electrostatic induced

Magnetic induced

Electromagnetic induced

Electric induced

Both A and C

A coil of constant area is placed in a constant magnetic field. An include current is produced in the coil when:

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The coil is destroyed

The coil is Rotated

The coil is neither destroyed nor rotated

Both (A) and (B)

None of these

The induced current in the loop can be Increased by

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Using a stronger magnetic field

Moving the loop faster

Replacing the loop by a coil of many turns

All above

Both A and B

For inducting emf in a coil the basic requirement is that:

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Flux should link the coil

Change in flux should link the coil

Coil should form a closed loop

Both B and C are true

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ECAT Pre General Science Physics Chapter 15 Electromagnetic Induction Online Test MCQs With Answers

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