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Fun with Magnets - 1

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Which of the following activities does not cause demagnetisation of magnets?

  1. Hitting

  2. Hammering

  3. Dropping

  4. Suspension


Correct Option: D
Explanation:

Suspension does not cause demagnetisation of magnets as poles in case of suspension are properly aligned in the north–south direction.

Which of the following is known as the world’s first natural magnet?

  1. Magnetite

  2. Bar magnet

  3. Iron

  4. Needle


Correct Option: A
Explanation:

Magnetite is known as the world’s first natural magnet.

Magnet was discovered in

  1. France

  2. China

  3. Greece

  4. Italy


Correct Option: C
Explanation:

Magnet was discovered in Greece.

What was the occupation of the person who discovered magnet?

  1. Carpenter

  2. Shepherd

  3. Farmer

  4. Tailor


Correct Option: B
Explanation:

The person who discovered magnet was a shepherd.

The opposite poles of two magnets

  1. repel each other

  2. attract each other

  3. do not show any interaction

  4. move clockwise


Correct Option: B
Explanation:

The opposite poles of two magnets attract each other as unlike charges or unlike poles attract each other.

Pick out the set of non-magnetic items from the given alternatives.

  1. Iron, cobalt, nickel

  2. Cloth, leather, scale

  3. Paper dip, iron gates, knives

  4. Fork, iron nails, grills


Correct Option: B
Explanation:

Cloth, leather and scale are non-magnetic in nature.

What are the materials which get attracted towards a magnet called?

  1. Conductors

  2. Magnetic materials

  3. Insulators

  4. Non-magnetic materials


Correct Option: B
Explanation:

The materials which get attracted towards a magnet are called magnetic materials.

Why should magnets be stored safely?

  1. Magnets become weak if handled carelessly.

  2. Magnets are expensive.

  3. Magnets break easily.

  4. Magnets attract all substances.


Correct Option: A
Explanation:

Magnets should be stored safely because they become weak and lose their magnetism if handled carelessly.

A freely suspended bar magnet points towards

  1. East

  2. North

  3. West

  4. South


Correct Option: B
Explanation:

A freely suspended bar magnet points towards North.

To prevent self-demagnetisation of a horseshoe magnet, a piece of _______ is kept across its poles.

  1. wood

  2. aluminium

  3. iron

  4. plastic


Correct Option: C
Explanation:

To prevent self-demagnetisation of a horseshoe magnet, a piece of iron is kept across its poles.

When a bar magnet immersed in a heap of iron filings is taken out, it is observed that the iron filings stick to the surface of the bar magnet. The iron filings would be observed to

  1. stick uniformly throughout the surface of the bar magnet

  2. stick randomly on the surface of the bar magnet

  3. have the maximum concentration at the two ends of the bar magnet

  4. have the maximum concentration slightly away from the two ends of the bar magnet


Correct Option: C
Explanation:

When a bar magnet immersed in a heap of iron filings is taken out, it is observed that iron filings stick to the surface of the bar magnet. The iron filings would be observed to have the maximum concentration at the two ends of the bar magnet.

A lot of wood powder, screws and iron nails are spread on the floor. How can you separate the items from the wood powder without wasting time?

  1. By handpicking

  2. By using a magnet

  3. By burning the wood powder

  4. Both (1) and (3)


Correct Option: B
Explanation:

By using a magnet, we can separate screws and iron nails wood powder without wasting time. This is because screws and iron nails are easily attracted by magnets.

Which of the following objects is/are not required while making a magnet?

  1. Cork

  2. Iron filings

  3. Bar magnets

  4. Needle


Correct Option: A
Explanation:

A cork is made up of rubber which is a good insulator and has no role in magnetism. So, cork is not required while making a magnet.

Why is it advised not to heat a magnet?

  1. Heating leads to demagnetisation.

  2. Heating increases the strength of the magnet.

  3. Heating breaks the magnet.

  4. Heating melts the magnet.


Correct Option: A
Explanation:

It is advised not to heat a magnet because heating leads to loss of magnetism or demagnetisation of the magnet.

Which of the following is a remarkable property of a magnet?

  1. Directive property

  2. Conductive property

  3. Inductive property

  4. Demagnetisation


Correct Option: A
Explanation:

The directional property of a magnet is remarkable. A magnetic compass, which is used to find direction, utilises the directional property of magnets.

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