Question 15 Marks
How will you test if a given substance is a magnet or not?
Answer
View full question & answer→Aim : To test whether a metallic bar is a magnet or not. Materials Required : An unidentified metallic bar and a bar magnet.
Procedure : Keep the unidentified metallic bar on a wooden table. Take a bar magnet and bring one of its poles close to one end of the metallic bar.
Observation and Conclusion :
1. If the bar is not attracted to the magnet, it means that the bar is made up of a non-magnetic material. So, it is definitely not a magnet.
2. If the bar is repelled by the magnet, it is definitely a magnet (fig- a)
3. If the bar is attracted to the magnet (fig. b), it may either be:
a. made of a magnetic material, or
b. a magnet that has its opposite pole facing the magnet. So, it requires further investigation.
Now bring the other pole of the magnet near the same end of the metallic bar.
4. If the bar is again attracted to the magnet (fig. c), it means that the metallic bar does not have magnetic poles. Hence, it is not a magnet.
5. If the bar is repelled by the magnet (fig. d), it clearly shows that this end of the bar has the same pole as the end of the magnet facing it (like poles repel). Hence, the metallic bar is a magnet. Thus, repulsion is the surest test for magnetism.
Procedure : Keep the unidentified metallic bar on a wooden table. Take a bar magnet and bring one of its poles close to one end of the metallic bar.
Observation and Conclusion :
1. If the bar is not attracted to the magnet, it means that the bar is made up of a non-magnetic material. So, it is definitely not a magnet.
2. If the bar is repelled by the magnet, it is definitely a magnet (fig- a)
3. If the bar is attracted to the magnet (fig. b), it may either be:
a. made of a magnetic material, or
b. a magnet that has its opposite pole facing the magnet. So, it requires further investigation.
Now bring the other pole of the magnet near the same end of the metallic bar.
4. If the bar is again attracted to the magnet (fig. c), it means that the metallic bar does not have magnetic poles. Hence, it is not a magnet.
5. If the bar is repelled by the magnet (fig. d), it clearly shows that this end of the bar has the same pole as the end of the magnet facing it (like poles repel). Hence, the metallic bar is a magnet. Thus, repulsion is the surest test for magnetism.