NCERT Class VI Science Solutions: Chapter 13 – Fun with Magnets Part 4

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LONG ANSWER QUESTIONS

Question 14:

Three identical iron bars are kept on a table. Two out of three bars are magnets. In one of the magnet the North-South poles are marked. How will you find out which of the other two bars is a magnet? Identify the poles of this magnet.

Answer:

The magnet with known poles will attract and repeat two ends of a magnet and attend both the end of an ordinary bar. (Test for repulsion)

Question 15:

Describe the steps involved in magnetising an iron strip with the help of a magnet.

Answer:

By rubbing the iron with a magnet as shown in the figure below.

Result for rubbing the iron with a magnet

Rubbing the Iron with a Magnet

Result for rubbing the iron with a magnet

Question 16:

Result for Compass

Compass

Result for Compass

Fig, shows a magnetic compass. What will happen to the position of its needle if you bring a bar magnet near it? Draw a diagram to show the effect on the needle on bringing the bar magnet near it. Also draw the diagram to show the effect when the other end of the bar magnet is brought near it.

Answer:

The magnetic needle of the compass will get deflected.

Result for The magnetic needle of the compass

The Magnetic Needle of the Compass

Result for The magnetic needle of the compass

Question 17:

Suggest an activity to prepare a magnetic compass by using an iron needle and a bar magnet.

Answer:

Hint: Magnetise the needle and set it in a way that it may rotate freely suspend it.

Question 18:

Boojho kept a magnet close to an ordinary iron bar. He observed that the iron bar attracts a pin as shown in Fig.

Result for magnet close to an ordinary iron bar

Magnet Close to an Ordinary Iron Bar

Result for magnet close to an ordinary iron bar

What inference could he draw from this observation? Explain.

Answer:

Hint: The magnetic properties are induced into the iron bar and it acts like a magnet till the magnet is kept near it.