Question

Question 28. A bar magnet with north and south poles marked N and S respectively and a bar
of iron PQ are fixed a short distance apart as shown in the figure. A compass needle is brought
in turn to the ends P, Q. N and S. Its north pole will point towards
(1 Point)
O A Both ends of the iron but only to the N pole of the magnet
B.Both ends of the iron but only to the S pole of the magnet
O End P only of the iron and only to the S pole of the magnet
D. End Q only of the iron and only to the spole of the magnet

Answer 1

Explanation:

. Laws of Magnetism Magnetic Properties of Matter Electromagnetism

2. State the properties of magnets.

3. Magnetism  The ancient Chinese discovered the magnetic property possessed by a certain type of natural iron ore called magnetite or lodestone in 2000 BC.  When suspend freely, this magnetic ore always points in a north-south direction.  The Chinese used this property to make a simple form of compass for navigational purposes.

4. Properties of Magnet  A magnets;  Has a magnetic field around it  Has two opposite poles which exert forces on other magnet  Will attract magnetic materials by inducing magnetism in them.  Will exert little or no force on a non- magnetic material.

5.  When a bar magnet is suspended freely in a paper stirrup, it always comes to rest in a north-south direction.  Its two points will always point in their respective fixed position, i.e. north pole pointed to the north and south pole pointed to the south.

6. Force Between Magnets  If two magnets are brought close together, they exert forces on each other.  If the north (N pole) of a bar magnet is brought near the N pole of another suspended magnet, the suspended magnet moves away.  Repulsion also occurs when two south poles (S poles) are brought near each other.  If the N pole is brought near a S pole, they are attracted to each other.

7. Law of Magnetism  Hence we can summarised the laws of magnetism:  Like poles repel each other.  Unlike poles attract each other.

8. Describe induced magnetism.

9. Induced Magnetism  Induced Magnetism is the magnetism of an object as a result of an external influence.

10.  When a magnet is brought near an iron rod, the rod becomes an induced magnet with one end nearer the magnet having opposite polarity to that of the magnet.  Thus induction always precedes attraction.