Fun with Magnets Q & A
Q.1. How will you do this?
(a) Determine whether a material is magnetic or non-magnetic.
Ans: To determine whether the material is magnetic or non-magnetic, i will bring that material near the magnet.If it sticks to the magnet, it is called magnetic material.If it doesn’t stick then it is non-magnetic.
(b) Explain that a magnet has a certain magnetic field.
Ans:
- The space around a magnet in which the magnetic force is active is called magnetic field.
- Place a white paper on a drawing board and place a magnet bar in the middle of the paper.
- Spread the iron filings on the sheet and tap the sheet.
- The iron filings arranged around the magnet in definite curved lines forming a symmetrical pattern.
- The lines are closer to each other near the poles and less crowded in the middle region around the magnet.
- The iron filings, will not get attracted beyond a particular region.
- The region where are iron filings attracted is the magnetic field of the magnets.
(c) Find the north pole of a magnet.
Ans: Tie a thread to the centre of a bar magnet and hang it from a stand.Note the direction in which the magnet settles and turn it around again.Let it settle and note the direction.The end of the magnet that points to the north is called the north pole, while the end that points to the south is called the south pole.The north pole is indicated by ‘N’ and the south pole by ‘S’.
Q.2. Which magnet will you use?
(a) Iron is to be separated from a trash.
Ans: I will use an electromagnet which is attached to a crane for loading and unloading, transporting scrap and loose iron material from a trash.
(b) You are lost in a forest.
Ans: If i will lost in a forest so i will use a bar magnet which will help me to indicate the north-south direction.
(c) A window shutter opens and shuts continuously in the wind.
Ans: I will use a bar magnet which can be attached to the window pane so that the window will be closed tight during the wind.
Q.3. Fill in the blanks with appropriate word.
(a) If a bar magnet is hung by a thread tied at its centre, its north pole becomes steady in the direction of the north pole of the earth.
(south, north, east, west)
(b) If a bar magnet is cut into equal pieces by cutting it at right angles to its axis at two pieces 3 bar magnets are formed, and a total of 6 poles are formed.
(6,3,2)
(c) There is a repulsion between the like poles of a magnet and attraction between its opposite poles.
(opposite, like.)
(d) When magnetic material is taken close to a magnet, the material acquires induced magnetism .
(permanent magnetism, induced magnetism, temporary, magnet keeper)
(e) If a magnet attracts a piece of metal, that piece must be made of magnetic material or iron.
(any other metal but iron, magnetic material or iron, non-magnetic material, electromagnets)
(f) A magnet remains steady in a north-south direction.
(east-west, north-south,)
Q.4. Write the answers in your words.
(a) How is an electromagnet made?
(b) Write the properties of a magnet.
Ans: The properties of a magnet:-
- The magnet always settles in the north-south direction.
- The magnetic force is concentrated at the two ends of a magnet.
- If a magnet is divided into two parts then two independent magnets are formed. That means that the two poles of a magnet cannot be separated from each other.
- A magnetic material acquires magnetism when placed near a magnet. This magnetism is called induced magnetism.
- There is repulsion between like poles while there is attraction between the opposite poles of a magnet.
(c) What are the practical uses of a magnet?
Ans: Magnets are materials to which objects made from iron, nickel, cobalt are attracted. But man explored magnets and its properties and made his life comfortable.Permanent Magnets are used in caps of pin holders, doors of fridges, doors of cupboards etc and Temporary magnets like electromagnets are used in electric bells, circuit of various machines, ATM card swipe machines, MRI- Magnetic Resonance Image, loudspeakers, electric cranes, microphones, Mariner’s compasses, etc.