science Flashcards
a region of space around an electrically charged particle or object in which an electric charge would feel force
electric field
The interplay of changing electric and magnetic field leads to the production of
electromagnetic waves
is produced by accelerating charged particles or particles oscillating about an equilibrium position, with the electric field and magnetic field vibrating perpendicularly to each other and to the direction of wave propagation.
electromagnetic wave
A Scottish physicist that predicted the existence of electromagnetic waves in 1862.
james clerk maxwell
In 1887, through the efforts of German physicist Heinrich Hertz, waves were observed to exist.
heinrich hertz
what is the unit of speed?
m/s
what is the unit of frequency?
f
what is the unit of wavelength?
meters
what is the speed of a vacuum?
3 x 10^8 m/s.
the speed of a vacuum is represented by what letter?
c
is the continuous range of EM waves arranged in order of frequency or wavelength.
electromagnetic spectrum
are formed when an electric field comes in contact with a magnetic field.
electromagnetic waves
The electric field and magnetic field of an EM wave are perpendicular to each other and to the direction of motion of the wave.
true
are the longest of all magnetic waves, ranging from 10-1 to 104.
radio waves
the oldest of all magnetic waves
radio waves
The frequency of ??? ranges from 3.0 x 104 to 3.0 x 1012 Hz or from 300 to 3000 MHz.
radio waves
This frequency is divided into specific bands for wireless communication.
radio waves
Low frequency, 30-300 khz
long distance communication navigation
medium frequency, 300-3000 khz
Amplitude moderation (AM) radio broadcasting
High frequency, 3-30 Mhz
Public transportation, electronic payment systems
very high frequency, 30-300 Mhz
frequency modulation (FM) radio broadcasting
ultra-high frequency, 300-3000 Mhz
police radio communications, modern cellphones
It makes use of radio waves for the detection of objects, weather forecasting, military surveillance and tracking satellites
radar
what are the uses of radio waves in technologies?
Automatic doors, Wi-Fi, bluetooth and GPS
what is the uses of radio waves in medical application?
Magnetic Resonance Imaging (MRI)
Reducing cellulite on the body and wrinkles and fine lines on the face
Tightening sagging or loose skin
Extraterrestrial Sources of Radio Waves
JUPITER AND SUN
They are generated by alternating current circuit attached to an antenna. It is also generated by electronic devices such as LC oscillators,which are electrical circuits.”
radio waves
lies somewhere between 3 x 108 Hz and 3 x 1011 Hz, which is from 300 MHz to 300 GHz, with a wavelength ranging from 10-3 to 10-1 m.
microwaves
is credited for discovering microwaves in 1864
james clerk maxwell
what is the use of microwaves in communication?
Sending signals for cable television, as well as video or audio feeds from production vans to broadcasting stations
Long distance telephone calls
what are the other uses of microwaves?
Remote sensing for disaster management and mapping
Weather forecasting
what are the uses of microwaves in medical applications?
Uses the heat of microwaves to shrink or destroy tumors
Used to assess and monitor progress of treatment of breast cancer
infrared literally means what?
below red
It has a lower frequency than the red part of the visible light.
infrared waves
ranges from 3 x 10^11 to 4 x 10^14 Hz, with a wavelength ranging from 7.5 x 10^-7 to 10^-3 m.
infrared waves
a British astronomer, discovered IR in 1800.
Sir william herschel
cannot be seen by the naked eye but it can be felt as heat.”
infrared radiation
what are the uses of infrared waves?
Used in remote controls of television sets, burglar alarm systems, night vision cameras and certain types of thermometers
Most computers, laptops, and printers are equipped with infrared data association ports that enable you to transfer and print data without connecting them to a cable
what are the uses of infrared waves in medical applications?
Physio-
therapists use heat lamps to heal sports injuries
Medical infrared imaging is used for diagnosis and prognosis in areas such as oncology, rheumatology, sports medicine and orthopedics.
EM radiations in the range of 4 x 10^14 to 8 x 10^14 Hz with corresponding wavelengths of 4 x 10^-7 to 8 x 10^-7 m are the only ones seen by the naked eye. This part of the EM spectrum is called
visible light
what object did isaac newton used when he discovered the visible light?
prism
discovered the range of wavelength in the visible light spectrum when he refracted white light with a prism.
isaac newton
what is the wavelength of red?
760 nm
what does nm mean?
nenometers
what is the wavelentgh of orsnge
610 nm
what are the uses of visible light?
Every device that has a viewable screen makes use of visible lights such as televisions, liquid crystal displays (LCDs), and touchpad devices
Visible light is also used by plants in photosynthesis
Laser is an acronym for
Light Amplification by Stimulated Emission of Radiation.
used in many medical procedures such as optical imaging, surgery, endoscopy and treatment.”
laser
radiation ranges from 8 x 1014 to 1017 Hz. And its wavelength range is 6 x 10-10 to 4 x 10-7.
ultraviolet radiation
Ultraviolet radiation is more popularly known as UV, which was discovered by German physicist
Johann wilhelm ritter
what are the 3 kinds of uv rays?
uva, uvb, uvc
It accounts for 95% of the solar UV reaching Earth.
It penetrates the dermis.
uva
Most UVB is filtered by the ozone in the atmosphere.
It affects the topmost layer (epidermis) of the skin.
uvb
UVC is almost completely absorbed by the atmosphere and does not reach Earth’s surface.
uvc
what are the sources of uv rays?
sun and special lamps
what are the uses of uv lights?
Used to detect forged bank notes
Makes the security marker ink that is used in signing bankbooks visible
used in forensic investigations at crime scenes
used to sterilize medical equipment and purify water
used in pest control devices
uv lights are more popularly known as?
black light
X-ray is sometimes called the
roentgen ray
X-ray is sometimes called the Roentgen Ray, in honor of its discoverer, German physicist
wilhelm conrad roentgen
have lower energy
than hard x-ray and can penetrate soft substances such as flesh and bones.
soft x-rays
have higher
energy and are mainly used in industries.
hard x-rays
ow are X-RAYS produced?”
by sun and other stars
when accelerated electrons hit a metal and some medical equipment
what are the uses of x ray?
used to detect abnormalities in the skeletal system
used in dental imaging
taking photographs of the internal body (CT scan)
used in airport security checks to scan passenger luggage
are given off by radioactive elements such as cobalt and cesium. These are highly penetrating waves because of their short wavelengths ranging from less than 10-14 to 10-17 m.
gamma rays
a French chemist and physicist that has been recognized as having discovered gamma rays in 1900.
paul villard
Sources of Gamma Rays
sun
interstellar clouds
remnants of supernova
what are the uses of gamma rays?
used in industries to detect cracks in metals and to sterilize equipment and commercial products
used to kill bacteria, insects and parasites that can cause foodborne diseases.
what is the use of gamma rays in medical application
used to destroy cancer cells in a process called radiotherapy
Planck’s constant that is equal to
6.63 x 10^-34 J.s.
he greenhouse effect resulting from the increased concentration of greenhouse gases as a result of human activity is called
enhanced effect
enhanced effect is also known as ??
anthropogenic greenhouse effect.”
