To Exploring Magnets

Exploring Magnets

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1. Fill in the blanks:

• (i) Unlike poles of two magnets attract each other, whereas like poles repel each other.
• (ii) The materials that are attracted towards a magnet are called magnetic materials.
• (iii) The needle of a magnetic compass rests along the north-south direction.
• (iv) A magnet always has two poles.

2. State whether the following statements are True (T) or False (F):

• (i) A magnet can be broken into pieces to obtain a single pole. (F) — Poles always exist in pairs.
• (ii) Similar poles of a magnet repel each other. (T) — Like poles repel.
• (iii) Iron filings mostly stick in the middle of a bar magnet when it is brought near them. (F) — They stick near the ends/poles.
• (iv) A freely suspended bar magnet always aligns with the north-south direction. (T) — It rests along north-south.

3. Column I / Column II (Interactions):

Pair	Interaction
N – N	Repulsion
N – S	Attraction
S – N	Attraction
S – S	Repulsion

4. Atharv's experiment (Steel U-clips):

• Iron filings/clips stick most near the ends (poles) of the magnet.
• Position A and C are ends; B is the middle.
• The likely observation is (i) 10 2 10.

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5. Identifying two magnets out of three bars:

• Use the property of repulsion.
• Bring any two bars together. If they repel, both are magnets.
• Iron is always attracted.

6. Finding poles of an unmarked magnet using a marked one:

• Suspend the unmarked magnet freely.
• Bring the marked magnet's North pole near one end.
• Repulsion means that end is the North pole.
• Attraction means it's the South pole.

7. Finding the North pole of an unmarked magnet without another magnet:

• Suspend the magnet freely from its middle.
• Let it come to rest.
• The end pointing in the north direction is its North pole.

8. Guessing Earth's poles from a compass:

• Earth behaves like a giant magnet.
• The compass North pole points towards Earth's geographic north direction.

9. Solving the mechanic's problem (screws falling):

• Magnetise the screwdriver.
• The steel screws will then be attracted to it.

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10. Ring magnets X and Y (not moving together):

• Reason: Like poles (N-N or S-S) are facing each other. Like poles repel.
• Way to bring them in contact: Reverse one magnet so unlike poles face each other. Unlike poles attract.

11. Polarity in Fig 4.17:

End	Pole	Comment
End 5	N
End 4	S	Attracts N at 5
End 3	N	Paired with S at 4
End 2	S	Attracts N at 3
End 1	N	Paired with S at 2
End 6	S	Paired with N at 5