Physics
Observe the given picture carefully and answer the following questions.
(a) What do you observe?
(b) What is this phenomenon called?
(c) Are there any other means to achieve the same purpose? Name them, if any.
Answer
(a) A bar magnet is being heated strongly over a flame using a tong which destroys its magnetism.
(b) It is called demagnetisation by heating.
(c) Yes, a magnet can also be demagnetised by :
- By rough handling
- By dropping the magnet on the floor or on a hard surface a number of times
- By hammering the magnet repeatedly
- By passing alternating electric current around the magnet
Related Questions
How can you demagnetise a magnet? Explain.
Observe the given picture carefully and answer the following questions.
(a) Label the various components in the picture.
(b) What does this picture represent?
(c) What happens when the switch is turned off?
(d) Explain why does this happen.
A student was studying about the properties of magnets. He compiled his notes in a table. However, there were some mistakes in the table. Correct the given table.
Property of Magnets Explanation Correction(s) Attractive property A magnet attracts all kinds of materials. Directive property The end of the magnet pointing towards the geographical north is the south pole and the end of the magnet pointing towards the geographical south is the south pole. Coexistence of poles When a magnet is broken into a half, the north pole and south pole are separated. True test for magnetism Like poles of the magnet attract each other while unlike poles repel each other. Strength of the magnet The strength of the magnet is uniform throughout its length. Roshan's parents gifted him magnets on his birthday. His parents told him that magnets could attract objects. He played with those magnets all day and experimented by attracting different materials onto it. He noticed that some materials got attracted to it while some didn't. After a few days, his magnets were not working well.
Now, answer the following questions.
(a) What materials do you think got attracted to the magnets?
(b) What materials do you think didn't get attracted to the magnets?
(c) Why do you think his magnets stopped working?
(d) What should Roshan do to fix his magnets?