Question 2: Write any two functions of metal detectors.

Step-by-step solution provided.

Question 4: What metals are used for making magnets?

Step-by-step solution provided.

Question 1: Earth is called as a gigantic magnet.

Step-by-step solution provided.

Question 1: Functions of metal detector.

Step-by-step solution provided.

Question 2: Write down the characteristics of magnets.

Step-by-step solution provided.

Question 3: Characteristic of magnetic lines of force

Step-by-step solution provided.

Question 5: What is an electromagnet?

Step-by-step solution provided.

Question 6: How can an electromagnet be made?

Step-by-step solution provided.

Maharashtra State Board Class 7 Science & Technology Solutions Chapter 19 Properties of a Magnetic Field - Digest Answers | Maharashtra Board Solutions

Q: Question 1: Column ‘A’ Column ‘B’ 1. Iron, nickel, cobalt a. Electromagnet 2. Doorbell magnet b. Permanent magnet 3. Nickel, cobalt, aluminium c. Iron, nickel, titanium, aluminium 4. Cupboard

Column ‘A’ Column ‘B’ 1. Iron, nickel, cobalt d. Magnetic metals 2. Doorbell magnet a. Electromagnet 3. Nickel, cobalt, aluminium f. Alnico 4. Cupboard magnet b. Permanent magnet 5. Lodestone e. Mariner’s compass 6. Nipermag c. Iron, nickel, titanium, aluminium

Maharashtra State Board Class 7 Science Solutions Chapter 19 Properties of a Magnetic Field

Class 7 Science Chapter 19 Properties of a Magnetic Field Textbook Questions and Answers

1. Write the appropriate terms in the blanks:

Question a.
The alloys called …………. and …………. are used for making industrial magnets.
Answer:
alnico, Nipermag

Question b.
A magnetic field can pass through ………… and …………..
Answer:
cardboard, bottle

Question c.
The intensity of a magnetic field is indicated by the lines of …………..
Answer:
force

Question d.
The real test of a magnet is ……………….
Answer:
repulsion

2. With whom should I pair up?

Question a.

Column ‘A’	Column ‘B’
1. Compass	a. The highest magnetic force
2. Door of a cupboard	b. Like poles
3. Repulsion	c. A magnet
4. Magnetic pole	d. A magnetic needle

Answer:

Column ‘A’	Column ‘B’
1. Compass	d. A magnetic needle
2. Door of a cupboard	c. A magnet
3. Repulsion	b. Like poles
4. Magnetic pole	a. The highest magnetic force

3. Write answers to the following questions:

Question a.
Distinguish between the two methods of making artificial magnets
Answer:

Single touch method	Double touch method
1. In this method, one magnet is used to magnetise the steel bar.	1. In this method, two magnets are used to magnetise the steel bar.
2. In this method, the magnet is dragged from one end of the steel bar to another end.	2. In this method, two magnets are dragged from the middle of the steel bar to the opposite directions.
3. As only one magnet is used to induce magnetism, this method is called single touch method.	3. As two bar magnets are used to induce magnetism, this method is called double-touch method.
4. The magnetism created by this method is of low strength and lasts for a short time.	4. The magnetism created by this method is of high strength and lasts for a longer time.

Question b.
Which substances are used for making electromagnets?
Answer:
The substances used for making electromagnets are, an iron nail, insulated copper wire, one or more batteries and a pair of wire strippers.

Question c.
Write a note on magnetic field
Answer:

Question d.
Why is a magnetic needle used in a compass?
Answer:

Question e.
Explain with the help of a diagram how the intensity and direction of the magnetic field of a bar magnet can be determined.
Answer:

4. Give detailed information about how the merchants of olden times used a magnet while travelling.

Question a.
Give detailed information about how the merchants of olden times used a magnet while travelling.
Answer:

Project:

Question a.
Obtain information about the function of metal detectors.

Class 7 Science Chapter 19 Properties of a Magnetic Field Important Questions and Answers

Write the appropriate terms in the blanks:

Question 1 Maharashtra Board Solution

The magnetic lines of force always run from the north pole to the ……………..

Solution & Step-by-Step Answer:

south pole

Question 2 Maharashtra Board Solution

The unit of magnetic field strength is ……………...

Solution & Step-by-Step Answer:

A/M (Amperes per metre)

Question 3 Maharashtra Board Solution

The earth behaves like a giant ………….

Solution & Step-by-Step Answer:

barmagnet

Question 4 Maharashtra Board Solution

The ……………. properties of magnetic field was proposed by scientist

Solution & Step-by-Step Answer:

Michael Faraday

Question 5 Maharashtra Board Solution

The region around a magnet where the magnetic force acts on an object is called the …………..

Solution & Step-by-Step Answer:

magnetic field

Question 6 Maharashtra Board Solution

The ……………. of the magnetic field can be obtained from the number of lines of force.

Solution & Step-by-Step Answer:

strength

Question 7 Maharashtra Board Solution

The function of the metal detector is based on ………….

Solution & Step-by-Step Answer:

electromagnets

Question 8 Maharashtra Board Solution

The magnetism is ………….. in the case of an electromagnet.

Solution & Step-by-Step Answer:

temporary

Match the following:

Question 1 Maharashtra Board Solution

Column ‘A’	Column ‘B’
1. Iron, nickel, cobalt	a. Electromagnet
2. Doorbell magnet	b. Permanent magnet
3. Nickel, cobalt, aluminium	c. Iron, nickel, titanium, aluminium
4. Cupboard magnet	d. Magnetic metals
5. Lodestone	e. Mariner’s compass
6. Nipermag	f. Alnico

Solution & Step-by-Step Answer:

Column ‘A’

Column ‘B’

1. Iron, nickel, cobalt

d. Magnetic metals

2. Doorbell magnet

a. Electromagnet

3. Nickel, cobalt, aluminium

f. Alnico

4. Cupboard magnet

b. Permanent magnet

5. Lodestone

e. Mariner’s compass

6. Nipermag

c. Iron, nickel, titanium, aluminium

Write True or False correct and rewrite the false statements:

Question 1 Maharashtra Board Solution

Material alnico is a mixture of aluminium, nickel and iron.

Solution & Step-by-Step Answer:

False. Alnico is an alloy of aluminium, nickel and cobalt

Question 2 Maharashtra Board Solution

Nipermag is alloy of iron, nickel, cobalt.

Solution & Step-by-Step Answer:

False. Nipermag is an alloy of iron, nickel, aluminium and titanium

Question 3 Maharashtra Board Solution

The magnetic force is concentrated at the centre of the magnet.

Solution & Step-by-Step Answer:

False. The magnetic force is concentrated at the poles of the magnet.

Question 4 Maharashtra Board Solution

Magnetism of electromagnet is permanent.

Solution & Step-by-Step Answer:

False. Magnetism of electromagnet is temporary

Question 5 Maharashtra Board Solution

Like poles attract each other and unlike poles repel each other.

Solution & Step-by-Step Answer:

False. Like poles repel each other and unlike poles attract each other

Question 6 Maharashtra Board Solution

Two poles of a magnet cannot be separated from each other.

Solution & Step-by-Step Answer:

True.

Answer in one or two sentences:

Question 1 Maharashtra Board Solution

In which direction does a freely suspended magnet settle?

Solution & Step-by-Step Answer:

The north pole of a freely suspended magnet settles in the direction of the geographic north pole of the earth. It settles in north-south direction.

Question 2 Maharashtra Board Solution

Write any two functions of metal detectors.

Solution & Step-by-Step Answer:

Question 3 Maharashtra Board Solution

Which magnetic poles attract each other?

Solution & Step-by-Step Answer:

Opposite magnetic poles attract each other.

Question 4 Maharashtra Board Solution

What metals are used for making magnets?

Solution & Step-by-Step Answer:

Give scientific reasons:

Question 1 Maharashtra Board Solution

Earth is called as a gigantic magnet.

Solution & Step-by-Step Answer:

Question 2 Maharashtra Board Solution

A bar magnet kept on the cardboard arranges the iron fillings in line.

Solution & Step-by-Step Answer:

Write short note on:

Question 1 Maharashtra Board Solution

Functions of metal detector.

Solution & Step-by-Step Answer:

Question 2 Maharashtra Board Solution

Write down the characteristics of magnets.

Solution & Step-by-Step Answer:

Question 3 Maharashtra Board Solution

Characteristic of magnetic lines of force

Solution & Step-by-Step Answer:

Can you tell?

Answer the following questions:

Question 1 Maharashtra Board Solution

Why does freely suspended magnet always settle in the north-south direction?

Solution & Step-by-Step Answer:

Question 2 Maharashtra Board Solution

Which magnetic poles attract each other?

Solution & Step-by-Step Answer:

Opposite magnet poles attract each other.

Question 3 Maharashtra Board Solution

Which pole of a spherical magnet will get attracted towards the south pole of the bar magnet?

Solution & Step-by-Step Answer:

The north pole of the spherical magnet will get attracted towards the south pole of the bar magnet.

Question 4 Maharashtra Board Solution

Why does a bar magnet kept at a distance doesn’t attract pins?

Solution & Step-by-Step Answer:

Question 5 Maharashtra Board Solution

What is an electromagnet?

Solution & Step-by-Step Answer:

Question 6 Maharashtra Board Solution

How can an electromagnet be made?

Solution & Step-by-Step Answer:

Use your brainpower!

Answer the following questions:

Question 1 Maharashtra Board Solution

Which direction will a magnetic needle show on the geographic north pole?

Solution & Step-by-Step Answer:

North, all magnetic needle will show north direction.

Question 2 Maharashtra Board Solution

Is magnetic force a vector or a scalar quantity?

Solution & Step-by-Step Answer:

Question 3 Maharashtra Board Solution

What is meant by magnetic force?

Solution & Step-by-Step Answer:

Question 4 Maharashtra Board Solution

How does a magnetic force act without direct contact?

Solution & Step-by-Step Answer:

Magnetic force acts without even direct contact because of the penetrating ability of the magnetic field.

Question 5 Maharashtra Board Solution

What is the difference between the gravitational force and magnetic force?

Solution & Step-by-Step Answer:

Gravitational Force	Magnetic Force
1. Gravitational force acts between any objects with mass.	1. Magnetic force acts between objects with specific properties.
2. It depends on the mass of the objects.	2. It does not depend on the mass of objects.
3. It acts over long-range as a gravitational field is large.	3. It acts over short-range as magnetic field is short.
4. Object are always attracted to each other.	4. Objects are either attracted or repelled.

Question 6 Maharashtra Board Solution

Why is repulsion the real test for identifying a magnet?

Solution & Step-by-Step Answer:

A magnet can attract the opposite pole of the magnet as well as magnetic substances (iron, cobalt, nickel). So if a magnet attracts another object, we cannot say that other object is a magnet or a magnetic substance. But if the magnet repels the object then we can surely say that the other object is a magnet because like poles of magnets repel each other.

Question 7 Maharashtra Board Solution

How will you find a magnet from among the various articles given to you?

Solution & Step-by-Step Answer:

Find out:

Answer the following questions:

Question 1 Maharashtra Board Solution

Why does the magnetic needle of a compass not settle parallel to the ground but at an angle to it?

Solution & Step-by-Step Answer:

Observe the diagrams and answer the questions given below:

Question 1 Maharashtra Board Solution

Name the methods shown.

Solution & Step-by-Step Answer:

Single touch and Double touch methods of magnetising a steel bar.

Question 2 Maharashtra Board Solution

Give 2 points of difference between the methods.

Solution & Step-by-Step Answer:

Single touch method	Double touch method
1. In this method, one magnet is used to magnetise the steel bar.	1. In this method, two magnets are used to magnetise the steel bar.
2. In this method, the magnet is dragged from one end of the steel bar to another end.	2. In this method, two magnets are dragged from the middle of the steel bar to the opposite directions.
3. As only one magnet is used to induce magnetism, this method is called single touch method.	3. As two bar magnets are used to induce magnetism, this method is called double-touch method.
4. The magnetism created by this method is of low strength and lasts for a short time.	4. The magnetism created by this method is of high strength and lasts for a longer time.

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Chapter 19 Properties of a Magnetic Field Solutions