Care and Storage of Magnets

Q.

Bar magnets are stored in pairs with their unlike poles on the_____side separated by a piece of wood and two pieces of______should be placed at their ends.

1. same
2. opposite
3. paper
4. soft iron

Q.

Question 1 (i)

Fill in the blank in the following.
Artificial magnets are made in different shapes such as ___, ___ and
___.

Q. The force experienced by each pole of a magnet kept in the magnetizing field of strength 30N/weber is 61000. Then magnetic moment of the magnet of length 10 cm.

Q.

A bar magnet is hammered for some time. Its magnetic strength:

1. is likely to increase

2. is likely to decrease

3. will not change

4. none of the above

Q.

State the advantages of artificial magnets over natural magnets.

Q.

The bar magnet is a ___________magnet.

Q.

Artificial magnets are more powerful than natural magnets.

1. True
2. False

Q.

Magnets should be kept inside a closed container because

1. it will repel substances made up of wood.

2. it will attract metal debris.

3. it will lose its magnetic property.

4. it will melt otherwise.

Q.

If you dip a magnet into bowls with iron filings, most of the iron filings get attracted to the ends of the magnet.

Q. To protect an instrument from external magnetic field, it is put inside an iron box.

1. True
2. False

Q.

What is magnetism?

Q. Ganeshan set up an experiment using two bar magnets one of which is marked N (North pole) and S (South pole) as shown in the figure. He noticed that the upper magnet is lifted up in air.

Identify X and Y poles of the upper magnet.

1. X is the north pole, Y is the south pole.
2. X is the south pole, Y is the north pole.
3. Both X and Y are north poles.
4. Both X and Y are south poles.

Q. The correct method of storing more than two bar magnets is to arrange them with their:

1. Unlike poles adjacent to each other
2. Unlike poles arranged in one direction with a strip of wood of same dimensions kept between them
3. Like poles arranged in one direction with a stripe of ferromagnetic material of same dimensions kept between them
4. Like poles adjacent to each other

Q.

Bar magnets should be stored

1. in pairs

2. in cold place

3. under UV rays

4. in water

Q. Assertion :To protect any instrument from external magnetic field, it is put inside an iron body. Reason: Iron is a magnetic substance.

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. Assertion is incorrect but Reason is correct

Q. Which of the following materials is best suited for making magnetic keepers ?

1. Steel
2. Iron
3. wood
4. Alnico

Q. The method of placing an iron plate between the poles of a temporary horseshoe magnet ___________.

1. Increases the poles strength
2. Decreases the poles strength
3. Helps keep their magnetic properties for a longer time
4. Does not affect the pole strength

Q. Permanent magnetism are demagnetized by:

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

Q. Soft iron pieces are placed across the ends of bar magnets when stored. Such pieces are called

1. Keepers
2. Compasses
3. Preservatives
4. Poles