Lesson Notes By Weeks and Term v4 - SHS 2
ELECTROMAGNETISM
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ELECTROMAGNETISM
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Subject: Physics
Class: SHS 2
Term: 2nd Term
Week: 6
Grade code: 2.3.2.LI.3
Strand code: 3
Sub-strand code: 2
Content standard code: 2.3.2.CS.1
Indicator code: 2.3.2.LI.3
Theme: ELECTRIC FIELD, MAGNETIC FIELD AND ELECTRONICS
Subtheme: ELECTROMAGNETISM
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Welcome, class! Today, we are exploring a fascinating and powerful principle at the heart of how so many machines work around us. Have you ever wondered what makes a ceiling fan spin, a blender chop your tomatoes, or an electric car move? The answer is the motor effect, a force that appears as if by magic when electricity meets magnetism. This principle is not magic; it is pure physics! We will learn the rule that helps us predict the direction of this force: Fleming's Left-Hand Rule.
A. The Motor Effect: The Fundamental Principle
When a wire carrying an electric current is placed in a magnetic field, it experiences a force. This is because the electric current itself creates its own magnetic field around the wire. The interaction between this new magnetic field and the original magnetic field produces a resultant force, causing the wire to move (if it is free to do so). This phenomenon is called the motor effect.
The force is strongest when the wire is perpendicular (at 90°) to the magnetic field lines. The force is zero if the wire is parallel to the magnetic field lines. B. Fleming's Left-Hand Rule (The Motor Rule)
To easily determine the direction of the force (or motion), we use a rule developed by John Ambrose Fleming. It is a simple but powerful tool.