MOST ESSENTIAL LEARNING COMPETENCY
• Define magnetic field, magnetic field lines, and magnetic flux.
• Identify the relationship of electricity and magnetism.
1. Define magnetic field, field lines, and flux.
2. Draw a diagram of the magnetic field lines.
3. Define electromagnetism.
4. Cite applications of electromagnetism and the scientists that paved way in discovering it.
• Electric field is defined as the electric force per unit charge.
• Electric Field lines are patterns points the direction that a positive test charge would
accelerate if placed upon the line.
• Electric flux is the rate of flow of the electric field through a given area.
• A superconductor is a material that can conduct electricity or transport electrons from one
atom to another with no resistance.
WHAT IS IT
Magnetism is one aspect of the combined electromagnetic force. It refers to physical phenomena arising from the force caused by magnets, objects that produce fields that attract or repel other objects. A magnetic field exerts a force on particles in the field. The motion of electrically charged particles gives rise to magnetism. The force acting on an electrically charged particle in a magnetic
field depends on the magnitude of the charge, the velocity of the particle, and the strength of the
All materials experience magnetism, some more strongly than others. Permanent magnets,
made from materials such as iron, experience the strongest effects, known as ferromagnetism. With
rare exception, this is the only form of magnetism strong enough to be felt by people.
MAGNETIC FIELD LINES
Magnetic field lines are defined to have the direction that a small compass points when placed at a location. Since magnetic forces act at a distance, we define a magnetic field to represent magnetic forces. The pictorial representation of magnetic field lines is very useful in visualizing the strength and direction of the magnetic field.
The properties of magnetic field lines can be summarized by these rules:
1. The direction of the magnetic field is tangent to the field line at any point in space. A small compass will point in the direction of the field line.
2. The strength of the field is proportional to the closeness of the lines. It is exactly proportional to the number of lines per unit area perpendicular to the lines (called the areal density).
3. Magnetic field lines can never cross, meaning that the field is unique at any point in space.
4. Magnetic field lines are continuous, forming closed loops without beginning or end. They go from the north pole to the south pole.
Magnetic flux is a measurement of the total magnetic field which passes through a given area. It is a useful tool for helping describe the effects of the magnetic force on something occupying a given area.
When a wire is moved in a magnetic field, the field induces a current in the wire. Conversely, a magnetic field is produced by an electric charge in motion.
Michael Faraday – law of electromagnetic induction which helps us to predict how a magnetic field would interact with an electric circuit to produce an electromotive force (EMF). This phenomenon is known as electromagnetic induction.
Hans Christian Oersted – demonstration on the relationship of electricity and magnetism.
Andre-Marie Ampere – first person to observe a connection between electricity and magnetism and was the first scientist to attempt to theoretically explain and mathematically describe the phenomenon. He also determined the shape of the magnetic field around a current carrying wire.
James Clerk Maxwell– developed a scientific theory to explain electromagnetic waves. He noticed that electrical fields and magnetic fields can couple together to form electromagnetic waves. Maxwell discovered that a CHANGING magnetic field would induce a CHANGING electric field and vice-versa.
The electromagnetic waves arranged in increasing frequency and energy but decreasing wavelength: Power waves, radio wave, microwave, infrared radiation, visible light, ultraviolet, x-ray, gamma ray.
Heinrich Friedrich Emil Lenz – Lenz’s law, in electromagnetism, statement that an induced electric
current in a direction such that the current opposes the change that