Electricity and magnetism are different facets of electromagnetism. This connection first elucidated by Faraday, Maxwell.
Faraday’s Law: A changing magnetic field will create an electric field. The direction of the electric field will be
perpendicular to the direction of the magnetic field.
Maxwell’s Proposal: A changing electric field will create a
magnetic field. The direction of the magnetic
field will be perpendicular to the direction of the electric field.
RELATION BETWEEN ELECTRICITY & MAGNETISM
A changing magnetic field
produces an electric field, and a changing electric field produces a magnetic
field.
Electric and Magnetic fields can
produce forces on charges
An accelerating charge
produces electromagnetic waves (radiation)
Both electric and magnetic fields
can transport energy
Electric field energy used in
electrical circuits, e.g., released in lightning
Magnetic field carries energy
through transformer
ELECTROMAGNETIC WAVE
The electromagnetic wave is
looked at as sinusoidal waves which are composed of a combination of two fields
which are i) electric field and ii) a magnetic field at right angle to that
electric field.
All electromagnetic radiation
travels at c = 3x108 m/s in
vacuum – real number is 299792458.0 m/s exactly
Examples of Electromagnetic Radiation
•
AM and FM radio waves (including TV signals)
•
Cell phone communication links
•
Microwaves
•
Infrared radiation
•
Light
•
X-rays
•
Gamma rays
Uses of Electromagnetic Waves
• Communication systems
•
Radar
•
Cooking (with microwaves)
•
Medical Imaging (X rays)
•
“Night Vision” (infrared)
•
Astronomy (radio, mwave,
IR, visible, UV, gamma)
