Permanent and Induced Magnetism for GCSE Physics

Introduction

Magnetism is a fascinating aspect of physics, and it plays a crucial role in our everyday lives. In GCSE Physics, understanding permanent and induced magnetism is essential for various topics.

Key Concepts

Permanent Magnets:
Magnets that retain their magnetism even after being removed from a magnetic field.
They are made of materials like iron, nickel, and cobalt.
Induced Magnets:
Materials that become magnetic only when placed in a magnetic field.
These materials lose their magnetism once removed from the field.

Properties of Permanent Magnets

Have two magnetic poles: north and south.
Opposite poles attract each other, while like poles repel.
Strength of a magnet is measured in teslas (T).
Magnets can create magnetic fields, which exert a force on other magnets and moving charges.

How to Induce Magnetism

Stroking: Rubbing a magnet over an iron bar repeatedly in the same direction.
Electromagnet: Creating a magnetic field using an electric current passing through a coil of wire.

Common Mistakes to Avoid

Assuming all metals are magnetic.
Mixing up the north and south poles of a magnet.
Thinking that magnets can only attract other magnets.

Practice Problems

Problem 1:

A magnet has a strength of 0.5 T. Calculate the magnetic force on a charge of 2 C moving at a velocity of 5 m/s perpendicular to the magnetic field.

Solution:

Force (F) = Charge (q) x Velocity (v) x Magnetic field strength (B)

F = 2 C x 5 m/s x 0.5 T

F = 5 N

Conclusion

Permanent and induced magnetism are fundamental concepts in GCSE Physics. By understanding these principles, you can develop a solid foundation for further studies in electricity and magnetism.

Exam Tips:
Practice drawing diagrams of magnetic fields.
Remember the rules for attraction and repulsion between magnetic poles.
Be able to apply formulas for magnetic force and field strength.
FAQ:
Q: What can weaken a permanent magnet?
A: Heat, dropping, and strong electric fields.
Q: How can I increase the strength of an electromagnet?
A: Increase the current, number of coils, or use a ferromagnetic core.