Electromagnets

Q. Differentiate between natural magnet and artificial magnets. Give an example of each.

Q.

Write any two uses of electromagnet.

Q. Temporary magnets retain their magnetism for a long time.

1. True
2. False

Q.

Draw a labeled diagram to show how an electromagnet is made.

Q. Define the term magnetic field of a magnet. How will you recognise it experimentally?

Q. Write true or false for this statement:
Artificial magnets are weaker than natural magnets.

Q.

What is an electromagnet? Give examples where it is used. [2 MARKS]

Q.

How can you make an electromagnet using an iron bar?

Q.

Temporary magnets are usually made up of ________.

Q. Write true or false for this statement:
A magnet can attract only a magnetic substance.

Q.

The most effective and quickest way of making a magnet from soft iron is by:

1. Placing it inside a coil carrying current

2. Induction

3. The use of permanent magnet

4. Rubbing with another magnet

Q. Which of the following is not an application of electromagnet?

1. MRI machine
2. Maglev train
3. Loudspeaker
4. Compass

Q.

An electric bell uses ________.

1. an electromagnet

2. a compass

3. a piece of lodestone

4. a permanent magnet

Q. Write true or false for this statement:
Magnetic keeper is a wooden piece.

Q.

Very strong magnet is:

1. magnetic compass

2. electromagnet

3. bar magnet

4. horse shoe

Q.

Which of the following is a magnetic substance?

1. Chinaware

2. Wood

3. Nickel

4. Glass

Q. What is an electromagnet ? Name two factors on which the strength of magnetic field of an electromagnet depends and state how does it depend on the factors stated by you.

Q.

Name the source of magnetic energy.

Q. Which of the following actions will decrease the strength of the magnetic field of an electromagnet ?

1. Using fewer loops of wire per metre in the coil
2. Decreasing the current in the wire
3. Removing the iron core
4. All of the above

Q.

An electromagnet becomes weaker when the amount of current through the coil increases.

1. True
2. False

Q.

Write three uses of an electromagnet.

Q. You are provided with two identical metal bars. One out of the two is a magnet. Suggest two ways to identify the magnet.

Q. What are magnetic keepers? Name its material.

Q. A temporary magnet is made of

1. cast iron
2. steel
3. soft iron
4. stainless steel

Q.

Consider the following statements :

(i) Soft iron conducts electricity

(ii) Soft iron is magnetic material

(iii) Soft iron is used for magnetic permanent magnets

(iv) Soft iron is used as electro magnet

1. (i) and (ii) are correct
2. (i) and (iii) are correct
3. (ii) and (iv) are correct
4. (i), (ii) and (iv) are correct

Q. State whether true or false :

1. True
2. False

Q.

Describe the uses of an electromagnet.

Q. What is electro magnet?

Q. State four uses of electromagnets.

Q.

An electromagnet is used to separate large mass of________________scrap.