Electromagnetic theory based on
Maxwell’s equations establishes the basic principle of electrical and electronic circuits over the entire frequency spectrum from dc to optics
. It is the basis of Kirchhoff’s current and voltage laws for low-frequency circuits and Snell’s law of reflection in optics.
What are the main points of electromagnetic wave theory?
The main points of electromagnetic wave theory were :
When an electrically charged particle moves under acceleration, alternating electrical and magnetic fields are produced and transmitted
. These fields are transmitted in the form of waves. These waves are called electromagnetic waves or electromagnetic radiations.
What is Maxwell’s electromagnetic theory?
In his formulation of electromagnetism, Maxwell
described light as a propagating wave of electric and magnetic fields
. More generally, he predicted the existence of electromagnetic radiation: coupled electric and magnetic fields traveling as waves at a speed equal to the known speed of light.
Why is the electromagnetic theory important?
EM theory is an
essential basis for understanding the devices, methods, and systems used for electrical energy
. Both electric and magnetic fields are defined in terms of the forces they produce. … EM theory is a vital tool for the design and operation of these lines and the many devices needed to connect to them.
What are the four Maxwell’s equations?
The four Maxwell equations, corresponding to the four statements above, are:
(1) div D = ρ, (2) div B = 0, (3) curl E = -dB/dt, and (4) curl H = dD/dt + J
. In the early 1860s, Maxwell completed a study of electric and magnetic phenomena.
What are the 4 main properties of electromagnetic waves?
Every form of electromagnetic radiation, including visible light, oscillates in a periodic fashion with peaks and valleys, and displaying a
characteristic amplitude, wavelength, and frequency
that defines the direction, energy, and intensity of the radiation.
What are the 7 types of light?
The EM spectrum is generally divided into seven regions, in order of decreasing wavelength and increasing energy and frequency. The common designations are:
radio waves, microwaves, infrared (IR), visible light, ultraviolet (UV), X-rays and gamma rays
.
How do we use electromagnetic energy?
Up to the end of the microwave spectrum, most all modern conveniences that use electromagnetic energy in one way or another are in the lower frequency region, including millimeter waves, cell phones, WiFi, microwave ovens, space and terrestrial communications, radar for airports and military uses,
AM and FM radio,
…
What is the effect of electromagnetic waves on human body?
Effects on general health
Reported symptoms include
headaches, anxiety, suicide and depression, nausea, fatigue and loss of libido
. To date, scientific evidence does not support a link between these symptoms and exposure to electromagnetic fields.
Why is it called electromagnetic?
Electromagnetic waves are produced by the motion of electrically charged particles. These waves are also called “electromagnetic radiation”
because they radiate from the electrically charged particles
.
How is electromagnet used in our society?
Electromagnets are widely used as
components of other electrical devices
, such as motors, generators, electromechanical solenoids, relays, loudspeakers, hard disks, MRI machines, scientific instruments, and magnetic separation equipment.
Is electromagnet a permanent magnet?
Electromagnets: A permanent magnet is
a magnet that retains its magnetion
. A small permanent magnet can be used to hold notes onto the door of a refrigerator. … An electromagnet is a temporary magnet which magnetic field is produced by the flow of electric current in a coil wound round a soft iron core.
What is Maxwell’s first equation?
∇⋅D=ρ
. This is the first of Maxwell’s equations.
What are the two Maxwell’s equations for magnetostatic fields?
Generally, the magnetic field in the presence of a current density J is given by Maxwell’s equation
(2): ∇ × H = J.
What are two key features of an electromagnetic wave?
Like other waves, electromagnetic waves have properties of
speed, wavelength, and frequency
.
