are electromagnetic waves?
electromagnetic wave as the name suggests is both an electric
and magnetic wave.
electromagnetic wave consists of an electric field and
a magnetic field at right angles to each other and to
the direction of the motion of the wave.
the electric and magnetic fields are at right angles to
the direction of the wave, the electromagnetic wave is
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radiation is classified into types according to the frequency
of the wave: these types include, in order of increasing frequency,
radio waves, microwaves, terahertz radiation, infrared radiation,
visible light, ultraviolet radiation, X-rays and gamma rays.
waves, electromagnetic waves to not carry energy by causing
matter to vibrate. It is the electric and magnetic fields that
vibrate. This is the reason why electromagnetic waves can travel
in a vacuum where there is no matter.
a particle or wave?
both wave and particle properties. This is also the case for
all matter. Electromagnetic radiation can be considered to consist
of particle-like packets of wave-energy called photons. These
massless particles travel at the speed of light (300,000 kilometers
per second in a vacuum).
is characterized by wavelength (the distance from the crest
of one wave to the crest of the next wave), by frequency (the
number of wave cycles that pass by in a given period, measured
in Hertz, which stands for cycles per second), and by the energy
it carries (measured in electron volts).
is the relationship between wavelength, frequency and energy
of Electromagnetic Radiation?
Planck constant (denoted h), also called Planck's constant,
is a physical constant reflecting the sizes of quanta
in quantum mechanics. It is named after Max Planck, one
of the founders of quantum theory. The Planck constant
was first described as the proportionality constant between
the energy (E) of a photon and the frequency of its associated
electromagnetic wave (v). This relation between the energy
and frequency is called the Planck relation or the Planck–Einstein
higher the frequency of light, the higher its energy.
Higher frequencies mean shorter wavelengths. We can also
say that E = h c / lambda (lamda is the wavelength). High
frequency light has short wavelengths and high energy.
X-rays or gamma-rays are examples of this. Radio
waves are examples of light with a long wavelength,
low frequency, and low energy.
electromagnetic waves produced?
are charged particles that can produce both an electric and
magnetic field. In order for electrons however to produce electric
or magnetic fields they must be in motion. A charged particle
such as an electron that moves back and forth creates both electric
and magnetic fields.
of all electromagnetic waves is charge that is changing speed
light is produced by electrons moving from one electronic
state to another
a ground state electron is excited it absorbs a photon.
The energy of the photon is equal to the energy needed
to maintain the electron at the higher orbital.
the electron returns to the ground state it will emit the
electromagnetic spectrum is a continuum of all electromagnetic
waves arranged according to frequency and wavelength.
The sun, earth, and other bodies radiate electromagnetic
energy of varying wavelengths.
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visible spectrum is the portion of the electromagnetic
spectrum that is visible to (can be detected by) the human
eye. Electromagnetic radiation in this range of wavelengths
is called visible light or simply light.
the visible spectrum as--
are the different types of Electromagnetic Waves?
The waves in the electromagnetic spectrum that have the longest
wavelengths and lowest frequency are called radio waves. Radio
waves are used to transmit information from the antenna of a
broadcasting station to the antenna of your radio or TV. In
astronomy radio waves are used to gain information from distant
stars using radio telescopes. Radio telescopes have the advantage
that radio waves are not blocked by conditions of the Earth's
atmosphere as light waves are.
the highest frequency of radiowaves. Their wavelength is only
a few centimeters long. While microwaves pass right through
some materials they absorbed by others. Water and some other
molecules found in food absorb microwaves and turn the energy
into heat. This is what makes a microwave oven work. Glass and
plastic do not absorb microwaves so do not heat up. Metal however
does absorb microwaves and that is why we can't put it inside
a microwave oven. Short
wavelength microwaves are used in radar devices.
Radar works by sending out short pulses of radio waves
and recording the time it takes for the reflected wave to be
picked up by the receiver.
---lies between the visible and microwave portions of the electromagnetic
spectrum. Shorter, near infrared waves are not hot at all -
in fact you cannot even feel them. These shorter wavelengths
are the ones used by your TV's remote control. Far infrared
waves we experience every day in the form of heat. The heat
that we feel from sunlight, a fire, a radiator or a warm sidewalk
waves are the only electromagnetic waves we can see. We see
these waves as the colors of the rainbow. Each color has a different
wavelength. Red has the longest wavelength and violet has the
shortest wavelength. When all the waves are seen together, they
make white light.
(UV) light-- is electromagnetic radiation with a wavelength
shorter than that of visible light, but longer than X-rays,
in the range 10 nm to 400 . Though these waves are invisible
to the human eye, some insects, like bumblebees, can see them.
It is ultraviolet waves that are responsible for causing our
sunburns. UV light cannot pass through glass unless it is made
-- have smaller wavelengths and therefore higher energy than
ultraviolet waves. We usually talk about X-rays in terms of
their energy rather than wavelength. X-rays are most known for
their use in medicine. Because your bones and teeth are dense
and absorb more X-rays then your skin does, images of your bones
or teeth are left on the X-ray film while your skin appears
have the smallest wavelengths and the most energy of any other
wave in the electromagnetic spectrum. These waves are generated
by radioactive atoms and in nuclear explosions. Gamma-rays can
kill living cells, a fact which medicine uses to its advantage,
using gamma-rays to kill cancerous cells.
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