Loss of Magnetic Property

Q. What are magnetic and non-magnetic substances ? Give two examples of each.

Q.

Why should magnets not be placed near TV or computers ?

Q.

Question 20

Suggest an arrangement to store a U shaped magnet. How is this different from storing a pair of bar magnets?

Q. State two ways in which a magnet can get demagnetized?

Q. Is it true that all the metals are magnetic in nature? Explain with an example.

Q. Choose the incorrect statement among the following.

1. A bar magnet loses its magnetic property when dropped from a certain height.
2. A bar magnet that has been demagnetised can't be converted to a magnet again.
3. A bar magnet which is heated beyond a certain temperature loses its magnetic property.
4. A bar magnet loses its magnetic property when hammered repeatedly.

Q. Assertion :Above Curie temperature, a ferromagnetic material becomes paramagnetic. Reason: When a magnetic material is heated to very high temperature, it loses its magnetic properties.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Q. Which of the following metals are magnetic in nature?

1. Copper, Lead
2. Aluminium, Copper
3. Cobalt, Nickel
4. Iron, Aluminium

Q. How can a magnet lose its magnetism ? How should magnets be stored so that they do not lose their magnetism gradually ?

Q. What are magnetic and non-magnetic substances ? Give two examples of each.

Q.

How do you demagnetize?

Q. What happens, when a magnetic substance is heated?

1. It loses its magnetism
2. It becomes a strong magnet
3. Does not effect the magnetism
4. Either (b) and (c)

Q. Is it true that all the metals are magnetic in nature? Explain with an example.

Q.

If a magnet is demagnetised if it is heated on a high temperature then will theagnet get demagnetised if it is cooled at low temperature

Q. A standard tape recorder used to save or load computer information is known as.

1. Magnetic tape
2. Cassette drive
3. Punched paper tape
4. Card punch
5. None of the above

Q.

A magnet always attracts wood.

1. False

2. True

Q. All magnetic materials lose their magnetic properties when :

1. Dipped in water
2. Brought near a piece of iron
3. Dipped in oil
4. Strongly heated

Q. It is advised to keep the magnets away from television, mobiles, CD and computers. Explain why ?

Q. A magnet can be completely demagnetized by which one of the following processes?

1. Breaking the magnet into small pieces
2. Heating it slightly
3. Applying a reverse field of appropriate strength
4. Dropping it into ice cold water

Q. Magnets lose their properties if :

1. heated strongly
2. A.C. is passed through them
3. dropped from a height
4. all of the above

Q. By which of the following activity, a magnet can loose its property?

1. Demagnetizing magnetic field
2. Excess of heating
3. Sudden shock
4. All of the above

Q. Which of the following methods can't be used to demagnetise a magnet?

1. Dropping
2. Heating
3. Rubbing
4. Cooling
5. Breaking
6. Hitting
7. Wetting
8. Kept Unused

Q.

A magnet always attracts wood.

1. False

2. True

Q. All magnetic materials lose their magnetic properties when:

1. Dipped in oil
2. Brought near a piece of iron
3. Dipped in water
4. Strongly heated

Q.

why it is said not to keep a magnet on a computer

Q. Which of the following statement is true?

1. Isolated magnetic poles do not exist.
2. Lodestone is an artificial magnet.
3. Magnetic materials attract as well as repel magnets.
4. The north pole of the magnetic needle points towards Earth's magnetic north pole.

Q. The magnetic properties of a magnet can be destroyed by:

1. Cutting
2. Rubbing
3. Cooling
4. Heating

Q.

Which of the following activities will result in the loss of magnetic properties?

1. By immersing a magnet in water at room temperature.

2. Heating

3. Hammering

4. Keeping a magnet idle for a long time

Q. The magnet can be completely demagnized by

1. Breaking the magnet into small pieces
2. Heating it slightly
3. Dropping it into ice cold water
4. A reverse field of appropriate strength

Q. Permanent magnetism are demagnetized by:

1. Heating
2. Hammering
3. Dropping from a height
4. Keeping in water