physics MCQs - 9th class Chapter 08 Mcqs

1

Which of the following is a magnetic material?

A

Brass

B

Copper

C

Cobalt

D

Wood

2

The real test to identify a magnet is:

A

Attraction

B

Repulsion

C

Heating

D

Stroking

3

If a bar magnet is broken into two pieces, each piece will have:

A

Only a North pole

B

Only a South pole

C

No poles

D

Both a North and a South pole

4

The magnetism that appears in a material only in the presence of a permanent magnet is called:

A

Permanent magnetism

B

Induced magnetism

C

Domain magnetism

D

Residual magnetism

5

Which material is commonly used to make temporary magnets?

A

Steel

B

Alnico

C

Soft iron

D

Copper

6

The region around a magnet where it exerts a force on other magnetic objects is called the:

A

Magnetic domain

B

Magnetic field

C

Magnetic flux

D

Magnetic axis

7

Magnetic lines of force appear to originate from the:

A

South pole

B

Center of the magnet

C

North pole

D

Equator of the magnet

8

The strength of the magnetic field is indicated by:

A

The length of the field lines

B

The color of the magnet

C

The spacing of the field lines

D

The weight of the magnet

9

Where is the magnetic field of a bar magnet the strongest?

A

At the center

B

Midway between the center and poles

C

Away from the magnet

D

Near the poles

10

A point where the magnetic field from one magnet cancels out the field from another is called a:

A

Magnetic pole

B

Neutral point

C

Strong point

D

Domain point

11

Permanent magnets are used in which of the following devices?

A

Circuit breakers

B

Moving coil loudspeakers

C

Magnetic relays

D

Telephone receivers

12

The process reverse to an electric generator is a(n):

A

Transformer

B

Electric motor

C

Loudspeaker

D

Capacitor

13

What kind of magnet is used in a telephone receiver?

A

Permanent magnet

B

Horseshoe magnet

C

Bar magnet

D

Electromagnet

14

What happens to an electromagnet when the electric current is stopped?

A

It becomes stronger

B

It reverses its poles

C

It no longer remains a magnet

D

It becomes a permanent magnet

15

The strength of an electromagnet can be increased by:

A

Decreasing the number of turns

B

Using a weaker battery

C

Increasing the number of turns in the coil

D

Using a wooden core

16

A device that uses a low current to activate another circuit with a high current is a:

A

Circuit breaker

B

Magnetic relay

C

Loudspeaker

D

Maglev train

17

What is the core of an electromagnet in a circuit breaker made of?

A

Steel

B

Copper

C

Soft iron

D

Aluminium

18

Maglev trains use forces that arise from:

A

Static electricity

B

Induced magnetism

C

Gravitational force

D

Nuclear force

19

The magnetic field produced by a solenoid is similar to that of a:

A

Bar magnet

B

Horseshoe magnet

C

Single moving charge

D

Flat disc magnet

20

The magnetism in a material is due to the motion of:

A

Protons

B

Neutrons

C

The entire atom

D

Electrons

21

Materials in which atoms behave like tiny magnets are called:

A

Diamagnetic materials

B

Non-magnetic materials

C

Paramagnetic materials

D

Insulating materials

22

Examples of paramagnetic materials include:

A

Copper and bismuth

B

Iron and steel

C

Aluminium and lithium

D

Wood and plastic

23

In which materials do the magnetic fields from electron motions add up to zero?

A

Ferromagnetic

B

Paramagnetic

C

Magnetic

D

Diamagnetic

24

Copper, bismuth, and water are examples of:

A

Paramagnetic materials

B

Diamagnetic materials

C

Ferromagnetic materials

D

Permanent magnets

25

Materials like iron, steel, and cobalt are known as:

A

Diamagnetic materials

B

Paramagnetic materials

C

Ferromagnetic materials

D

Non-magnetic materials

26

A highly magnetized region of about 0.1 mm in a ferromagnetic material is called a:

A

Magnetic field

B

Magnetic domain

C

Magnetic pole

D

Magnetic dipole

27

How can an unmagnetized piece of iron be magnetized?

A

By cooling it

B

By placing it in an external magnetic field

C

By rubbing it with wood

D

By dropping it

28

Which material retains its magnetic alignment and is used for permanent magnets?

A

Soft iron

B

Copper

C

Steel

D

Aluminium

29

The method of magnetizing a steel bar by stroking it several times in the same direction with one pole is called:

A

Double-touch method

B

Induction method

C

Single-touch method

D

Electrical method

30

According to the Right-Hand Grip rule for a solenoid, the thumb points to the:

A

Direction of current

B

South pole

C

North pole

D

Negative terminal

31

How can a magnet be demagnetized?

A

By cooling it slowly

B

By placing it in a stronger magnetic field

C

By heating it strongly

D

By stroking it with another magnet

32

Beating a magnet with a hammer causes it to be:

A

Magnetized

B

Strengthened

C

Demagnetized

D

Re-aligned

33

Magnetic tapes are typically coated with a layer of:

A

Paramagnetic material

B

Diamagnetic material

C

Ferromagnetic material

D

Non-magnetic material

34

In a tape recorder, the recording head is a coil of wire wrapped around a(n):

A

Plastic core

B

Iron core

C

Copper core

D

Aluminium core

35

The curved part of the magnetic field from the recording head that penetrates the tape is called the:

A

Core field

B

Gap field

C

Fringe field

D

Stray field

36

What material property is described as the ability to allow magnetic flux to pass through it?

A

Permeability

B

Resistance

C

Capacitance

D

Conductivity

37

Why is soft iron used for magnetic shielding?

A

It has low permeability

B

It has high permeability

C

It is a permanent magnet

D

It repels magnetic fields

38

The sensitivity of a moving coil galvanometer is increased by placing what inside the coil?

A

A steel core

B

A soft iron core

C

A copper core

D

An aluminium core

39

When freely suspended, a magnet always settles in which direction?

A

East-West

B

North-South

C

Up-Down

D

Any random direction

40

If the N-pole of one magnet is brought near the N-pole of another, they will:

A

Attract

B

Repel

C

Have no effect

D

Become one magnet

41

Electromagnets are a type of:

A

Permanent magnet

B

Natural magnet

C

Temporary magnet

D

Diamagnetic material

42

What did the ancient Greeks discover that could attract materials containing iron?

A

Quartz

B

Lodestone

C

Granite

D

Obsidian

43

A magnetic compass needle's arrow symbolises the:

A

South pole

B

Direction of current

C

North pole

D

East direction

44

The magnetic field is weaker in regions where the field lines are:

A

Closer together

B

Far apart

C

Curved

D

Straight

45

Which method is more efficient for magnetizing a steel bar?

A

Single-touch method

B

Hammering method

C

Heating method

D

Double-touch method

46

In hard disk recording, a magnetic head writes a binary digit by:

A

Heating tiny spots

B

Magnetising tiny spots

C

Erasing tiny spots

D

Creating holes in the disk

47

To protect sensitive electronic devices from magnetic fields, they are enclosed in boxes made of:

A

Steel

B

Plastic

C

Aluminium

D

Soft iron

48

The magnetic properties of an electromagnet are lost when:

A

It is heated

B

It is hammered

C

The current is stopped

D

It is cooled

49

What is a common use for electromagnets in scrapyards?

A

Sorting plastics

B

Lifting and moving iron and steel objects

C

Crushing cars

D

Measuring weight

50

The end of a magnet that points towards the geographic south is called the:

A

North magnetic pole (N)

B

West pole

C

East pole

D

South magnetic pole (S)