1. How will you do this ?
(a) Determine whether a material is magnetic or non-magnetic.
ANSWER: To determine whether a material is magnetic or non-magnetic we bring it in contact with a magnet. If the material sticks to the magnet then the material is magnetic, else non-magnetic material.
(b) Explain that a magnet has a certain magnetic field.
ANSWER: The space around a magnet where the effect of magnetic force is active is said to be the magnetic field of that magnet.
Explanation:
Take a white paper and place some iron filing on it. Then bring a bar magnet in contact with the iron fillings. We can see a pattern set when the iron filling stick to the bar magnet. The intensity of the attracted iron filling is greater at the poles than at centre of the bar magnet. The region where the bar magnet holds the iron filling are said to be in the effect of magnetic field.
(c) Find the north pole of a magnet.
ANSWER: To find the north pole of a magnet do the following steps. Take a bar magnet and hang it to a hook using a thread. Now let the bar magnet get stable. After few minutes we can see that magnet points in the north-south direction. The end of the bar magnet that points towards the north direction is said to be the north pole of the magnet. In this way we can find the north pole of a magnet.
2. Which magnet will you use ?
(a) Iron is to be separated from trash.
ANSWER: To separate iron from thrash we can use electromagnet.
(b) You are lost in a forest.
ANSWER: To find direction we can use a simple bar-magnet.
(c) A window shutter opens and shuts continuously in the wind.
ANSWER: We can use a bar-magnet to shut the window.
3. Fill in the blanks with the 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 ……………. Pole of the earth. (South, north, east, west)
ANSWER: north
(b) If a bar magnet is cut into equal pieces by cutting it at right angles to its axis at two places, ……….. bar magnets are formed, and a total of ……………. poles are formed. (6,3,2)
ANSWER: 3, 6
(c) There is repulsion between the ………. poles of a magnet, and attraction between its ………… poles. (opposite, like.)
ANSWER: like, opposite
(d) When magnetic material is taken close to a magnet, the material acquires …………… . (permanent magnetism, induced magnetism)
ANSWER: induced magnetism
(e) If a magnet attracts a piece of metal, that piece must be made of …………. . (any other metal but iron, magnetic material or iron, non-magnetic material)
ANSWER: magnetic material or iron
(f) A magnet remains steady in a ………….. direction. (east-west, north-south)
ANSWER: north-south
4. Write the answers in your words.
- How is an electromagnet made ?
ANSWER: When magnetism is produced in a material due to the electric current such a magnet is called an electromagnet. Electromagnets are temporary magnets.
Procedure:
Take an iron nail of about 10 cm length and a 1-metre long insulated copper wire, a battery cell, pins or other magnetic objects.
Wind the copper wire around the nail. Join both the ends of the wire to the cell. Now take the pins near the head of the nail. We can see that the pin is attracted towards the nail. Thus a electromagnet is made.
- Write the properties of a magnet.
ANSWER: Following are the properties of magnet.
- A magnet always settles in the north-south direction.
- The magnetic force is concentrated at the two ends or poles of a magnet.
- If a magnet is divided into two parts, two independent magnets are formed. It 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 of a magnet, while there is attraction between the opposite poles.
What are the practical uses of a magnet ?
ANSWER: Practical uses of magnets are :
Permanent magnets:
- Used as pin holder
- Used in the door of a cupboard
- Magnetic compass
Temporary magnets:
- Door bell
- Crane
- Loudspeakers
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Also view: The Universe | General Science | Class 6
Dr. Ganesh Visavale 
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