CAPACITANCE Mechanical Waves
Capacitor - Not capable of transmitting its energy
through a vacuum
- is a system that stores energy in the - Requires a medium
form of an electric field. - Transverse
Capacitance C of the capacitor - Longitudinal
- the ratio Q/V is always the same for a
particular capacitor
Parallel- Plate Capacitor
Electromagnetic Waves
- A capacitor that consists of parallel - Capable of transmitting its energy
plates each of area A separated by the through a vacuum
distance d has a capacitance - Produced by the vibration of charged
Capacitors in Parallel Circuit particles
- The periodic changes occur in electric
- are connected together in parallel when and magnetic fields
both of its terminals are connected to
each terminal of another capacitor. Transverse wave
Capacitors in Series - The particles of the medium move
perpendicular to the direction of the
- are connected together in series when propagation of the wave
they are daisy chained together in a - Crest - highest part of the wave
single line. - Trough - lowest part of the wave
- Wavelength - the distance between
INDUCTORS
two successive crests, or two successive
- It is a device placed in a circuit to troughs, or between two successive
oppose a change in current; that is, to positions along the wave that are exact
maintain, and regulate, a steady current duplicates of one another
in that section of the circuit. - Amplitude - maximum height of crest
WAVE Longitudinal waves
Wave motion - The particles of the medium move
parallel to the propagation of the wave
- is a form of disturbance which travels - Compression - a region in
through a medium due to repeated longitudinal wave where the
periodic motion of the particles of the particles are closest together.
medium about their mean positions - Rarefaction - a region in a
longitudinal wave where the
Types of Waves
particles are furthest apart.
SOUND WAVE - reduces the energy of electromagnetic
waves by means of the reflection,
- are examples of longitudinal waves: absorption, and multiple reflection of
the individual particles (air molecules) the waves
vibrate back and forth in the direction
that the sound is traveling. Reflection loss
- is characterized as a mechanical wave.
- loss occurs at the boundary between
Ocean waves or Rayleigh Surface Waves the shielding material surface and the
air.
- are combinations of longitudinal and
transverse wave motion. Absorption loss
Sound - loss occurs due to the excess current
that is generated when the
- is a mechanical wave that results from electromagnetic wave passes through
the back and forth vibration of the
the shielding material.
particles of the medium through which
the sound wave is moving. Multiple reflection loss
- motion of the particles is parallel (and
anti-parallel) to the direction of the - loss occurs where the electromagnetic
energy transport. This is what wave is reflected repeatedly in the
characterizes sound waves in air as shielding material
longitudinal waves. Wavelength
LONGITUDINAL WAVES - . The horizontal distance between two
- the motion of the individual particles of consecutive troughs or crests
the medium is in a direction that is Red light
parallel to the direction of energy
transport - of 7×10-7 meters, or 700 nanometers
- can be created in a slinky if the slinky is (nm)
stretched out in a horizontal direction - 430 trillion hertz
Violet light
ELECTROMAGNETIC WAVES - of 4× 10-7 meters, or 400 nm
- 750 trillion hertz
Electromagnetic radiation
Gamma rays
- is one of the many ways that energy
travels through space. - 3 billion hertz (3 x 1019)
Electromagnetic wave shield Frequency
- is the number of waves that pass a - is the portion of the electromagnetic
point in space during any time interval, spectrum that is visible to the human
usually one second eye
- A typical human eye will respond to
wavelengths from about 380 to
740 nanometers. In terms of frequency,
this corresponds to a band in the
Light vicinity of 430–770 THz.
- is an electromagnetic wave. As light Reflected wavelengths
travels through space an electric field
and a magnetic field oscillate - are the ones we see and determine the
perpendicular to the wave direction and color of an object.
perpendicular to each other.
Visible light
Wave - is a combination of many wavelengths
- small disturbance in an electric field (colors), which give it a white
creates a small magnetic field, which in appearance
turn creates a small electric field
Color of light
- is determined by its wavelength. Electromagnetic Spectrum 1
Photons Radio waves
- Light undergoes interference and - are very long wavelength photons with
diffraction, as all waves do, but
wavelengths longer than a meter or so.
whenever light is emitted, it is always
done so in discreet of packets called Microwaves
Amplitude - are at the upper end of the radio part of
the spectrum
- Corresponds to brightness
Infrared wavelengths
Visible light
- are just longer in wavelength than the
- have such high frequencies, their wave- visible spectrum
lengths are very short.
Ultraviolet waves
Wave speed
- are just shorter in wavelengths than
- v = f visible waves
Visible Spectrum X-ray
- mostly from stellar sources, and can Reflectors
penetrate many materials, like skin,
muscle and bone. - are typically fixed on various roads
where they are used to indicate
Gamma rays bending roads etc.
- have the shortest wavelength CHROMATIC DISPERSION
TOTAL INTERNAL REFLECTION - results from the fact that the speed of
light in glass depends on the
- complete reflection of a ray wavelength of the light.
of light within a medium such as water - The dispersion of white light into its
or glass from the surrounding surfaces constituent colors is caused by a
back into the medium variation of the index of refraction of
Critical angle glass with color
- The phenomenon occurs if the angle of Chromatic aberration
incidence is greater than a certain
- When a single lens images a distant
limiting angle, called white-light point source, such as a star,
water-air surface the image is slightly distorted because
of dispersion in the lens; this effect is
- the critical angle is 48.5° called
Glass prisms Reflecting telescopes
- can be shaped to produce total internal - the imaging and magnification are
reflection and as such are employed in accomplished with mirrors
binoculars, periscopes, telescopes, and
other optical instruments. Rainbow
right angled isosceles prism - is formed when sunlight is refracted by
spherical water droplets in the
- These prisms can turn light through 90 atmosphere; two refractions and one
and 180 degrees based on internal reflection, combined with the
reflection. chromatic dispersion of water, produce
the primary arcs of color.
Laws of geometrical optics
optic fiber
- explain the formation of mirages and
- is as thick as human hair. they are
halos and the rarely observed “green
composed of fine quality glass or quartz
flash” of a setting Sun.
fiber and coated with a thin layer of
material with lower refractive index. Wave of light
- has a speed in a transparent medium - is thicker in the middle than on its
that varies inversely with the index of outside edge
refraction (a measure of the angle by
which the direction of a wave is Concave lenses
changed as it moves from one medium - are thicker on the ends and thinner in
into another). the middle.
Dispersion WAVES
- is sometimes called the separation of Wave motion
light into colors, an effect more
properly called angular dispersion. - is the transfer of energy and
momentum from one point of the
medium to another point of the
medium without actual transport of
Mirrors
matter between two points.
- reflect light and create images in a way
similar to a lens, depending on where Sound
an object is located in relation to a - is a vibration that typically propagates
mirror. as an audible wave of pressure, through
a transmission medium such as a gas,
plane mirror
liquid or solid.
- is a flat mirror that sends light out from
- is the reception of such waves and
itself in multiple directions.
their perception by the brain.
convex mirror
Sound spectrum
- works like a concave lens. It curves light
away from its middle, like the outside - is a representation of a sound – usually
portion of a bowl. This type of mirror a short sample of a sound – in terms of
will produce only smaller and virtual the amount of vibration at each
images. individual frequency
concave mirror Refraction
- It bends light further away in the - occurs because light travels at different
middle, more like the inside of a bowl. speed in air and water.
- Refraction is the bending of a wave
Lens when it enters a medium where its
speed is different
- refracts light and creates an image that
is either virtual or real Interference
convex lens
- The phenomenon that occurs when the Mirage
light waves collide with each other is
called - is produced by the refraction of light as
it travels the boundary between hot
ILLUMINATION and cold air.
- is the deliberate use of light to achieve Index of Refraction
a practical or aesthetic effect
- measure of the optical density of a
Lighting material. Ratio of the speed of light in
vacuum to the speed of light in another
- includes the use of both artificial light
material
sources like lamps and light fixtures, as
well as natural illumination by Virtual images
capturing daylight
- are images that are formed in locations
Daylighting where light does not actually reach.
Light does not actually pass through the
- is sometimes used as the main source
location on the other side of the mirror;
of light during daytime in buildings. This it only appears to an observer as though
can save energy in place of using the light is coming from this location.
artificial lighting, which represents a
major component of energy Pitch
consumption in buildings
- The frequency of a sound wave is what
Wavefronts your ear understands as
- The technical term for ripples Timbre
Rays - Also describes the term quality
- The arrows are pointing in the direction
the waves are moving, and they are
called
Snell’s law
- The amount of bending depends on
the indices of refraction of the two
media and is described quantitatively
by
Huygen’s principle
- The bending of refraction can be
visualized in terms of
