Term Test Flashcards
(29 cards)
Transverse waves particle movement:
Particles move in a perpendicular direction to the energy transfer
Longitudinal wave particle movement:
Particles move in a parallel direction to the energy transfer
Rarefaction
Particles spread apart in a wave
Compression
Particles close together in a wave
Wavelength
Distance from crest to crest
Amplitude
Max disturbance above rest point
Frequency
Number of waves per second
Time period
Time for 1 complete wave to pass a point
Two uses of ultrasound waves:
Cleaning watches and breaking up kidney stones
What is the human hearing range of frequencies of sound?
20hz-20000hz
Why can’t sound waves travel through a vacuum?
Because there are no particles for vibrations to take place.
How is ultrasound used in foetal scanning?
The transducer converts the sound waves into an electronic image on a computer screen.
How is an X-ray photograph taken?
Special machine emits (puts out) a small amount of ionising radiation. This radiation passes through your body and is captured on a special device to produce the image.
Which is safer, X-rays or ultrasound?
Ultrasound because it does not use ionising radiation which X-rays do so they do not have the same risks.
What’s the speed of all electromagnetic waves?
3.0 * 108 meters per second
Use and danger of X-rays:
X-ray scans can diagnose possibly life-threatening conditions such as blocked blood vessels, bone cancer, and infections. However, x-rays produce ionizing radiation—a form of radiation that has the potential to harm living tissue.
Ultraviolet danger and use:
UV lamps disinfect surfaces without chemicals, which is crucial in many industries. Excessive exposure to ultraviolet radiation is associated with different types of skin cancer, sunburn, accelerated skin aging, as well as cataracts and other eye diseases.
Infrared use and danger:
Infrared (IR) light is used by electrical heaters, cookers for cooking food, short-range communications like remote controls, optical fibres, security systems and thermal imaging cameras which detect people in the dark. The heating effect of IR can cause burns to the skin.
Use and danger of gamma rays:
Gamma rays can destroy living cells, produce mutations, and cause cancer. They can be used to treat cancer by focusing the deadly rays on cancer cells.
Uses and dangers of microwaves:
Microwaves are used for cooking food, communications and for satellite communications. Intense sources of microwaves can be dangerous through internal heating of body cells.
Uses and dangers of visible light:
Light allows us to perceive our surroundings using our eyes. If the irradiance exceeds certain levels, light can also be harmful – especially to the eyes.
Uses and dangers of radio waves:
Tissue damage to humans when exposed to high levels of RF levels, but radio waves are used for communication such as broadcasting television and radio, communications and satellite transmissions.
Wavefront:
A wave front is defined as a surface over which the phase of the wave is constant.
Transmit:
Pass through
