Keywords - Physics Flashcards
Wave
Transmitter of energy without the movement of particles from place to place.
Transverse wave
Waves involving the vibration of particles perpendicular to the direction of energy transfer.
Compression wave
Wave involving the vibration of particles in the same direction as the energy transfer.
Longitudinal wave
Another name for compression wave.
Medium
The material through which waves travel.
Vibrations
Repeated fast back and forth movements
Compression
Region in which particles are closer together than when not disturbed by waves.
Rarefaction
Region in which the particles are further apart than when not disturbed by waves.
Frequency
Number of vibrations in one second, or the number of wavelengths passing in one second.
Hertz
Unit of frequency, equal to one vibration per second. Abbreviated to Hz.
Pitch
Highness or lowness of a sound. The pitch depends on the frequency of the vibrations.
Wavelength
The distance between two neighbouring crests or troughs.
Amplitude
The maximum distance that a particle moves away from its undisturbed position.
Sonar
The use of soundwaves to locate objects under water (SOund Navigation And Ranging).
Echolocation
The use of sound to locate objects by detecting echoes.
Ultrasound
Sounds with frequencies too high for humans to hear.
Ear canal
The tube that leads from outside the ear to the eardrum.
Eardrum
A thin piece of stretched skin inside the ear that vibrates when sound waves reach it.
Membrane
A thin layer of tissue.
Auricle
The fleshy outside part of the ear, also called the pinna.
Cochlea
The snail shaped part of the ear. It is lines with tiny hairs that are vibrated by sound and stimulate the hearing receptors.
Semicircular canals
Three curved tubes, filled with fluid, in the the inner ear that control your balance.
Auditory nerve
A large nerve that sends signals to the brain from the hearing receptors in the cochlea.
Ossicles
A set of three tiny bones that send vibrations from the eardrum to the inner ear. They also make the vibrations louder.
Oval window
An egg shaped hole covered in thin tissue. It is the entrance from the outer ear to the inner ear.
Relative intensity
A measure of how loud a sound is using a sound meter.
Sound level
The energy of a sound, which is an indication of how loud the sound is.
Decibel (dB)
A unit of measurement of relative sound intensity.
Threshold of hearing
The lowest level of sound that can be heard by a human.
Threshold of pain
The lowest level of sound that causes pain to the human ear.
Tinnitus
A ringing or similar sensation in the ears, caused by damage to the cells of the inner ear.
Cochlear implant
A device implanted behind the ear that detects and processes sound, then sends signals to the auditory nerve, so that severely deaf people can hear. This is also called a bionic ear.
Electromagnetic spectrum
Complete range of wavelengths of energy radiation as electric and magnetic fields.
Radiowaves
Low energy electromagnetic waves with a much lower frequency and longer wavelength than visible light.
Infra red radiation
Invisible radiation felt as heat, emitted by all warm objects.
Visible light
A very small part of the electromagnetic spectrum, to which our eyes are sensitive.
Ultraviolet light
Invisible radiation similar to light, with a slightly higher frequency and more energy.
X-rays
High energy electromagnetic waves that can be transmitted through solids and provide information about their structure.
Gamma rays
High energy electromagnetic radiation produced during nuclear reactions. They have no mass and travel at the speed of light.
Electromagnetic waves
Electromagnetic energy that is transmitted as moving electric and magnetic fields.
Rays
Narrow beams of light.
Beam
Wide stream of light rays, all moving in the same direction.
Reflection
Light bouncing off the surface of a surface.
Luminous
An object that releases its own light.
Scattering
Describes light sent in many directions by small particles within a substance.
Transparent
Describes a substance that allows most light to pass through it.
Translucent
Allowing light to come through imperfectly, as in frosted glass.
Opaque
Describes a substance that does not allow any light to pass through it.
Concave
Curved inwards.
Convex
Curved outwards.
Focal point
The focus for a beam of light rays.
Lateral inversion
Reversed sideways.
Refraction
Change in the speed of light as it passes from one substance into another. It usually involves a change in direction.
Normal
A line drawn perpendicular to a surface at a point where a light Ray meets it,
Image
Picture of an object.
Retina
Curved surface at the back of the eye. It is lined with sight receptors.
Optic nerve
Large nerves that send signals to the brain from the sight receptors in the retina.
Cornea
The curved, clear, outer covering of the eye.
Lens
A transparent curved object that bends light towards or away from a point called the focus. The eye has a jellylike lens.
Iris
Coloured part of the eye that opens and closes the pupil to control how much light is let in.
Pupil
A hole through which light enters the eye.
Converging lens
A lens that bends light so that they move towards each other.
Diverging lens
A lens that bends light rays so that they move further apart.
Biconvex
A lens that is bent outwards on both sides.
Biconcave
A lens that in bent inwards on both sides.
Transmitting antenna
Metal structure in which vibrating electrons cause radio waves to travel through the air.
Receiving antenna
Metal structure in which electrons are made to vibrate by radio waves or microwaves in the atmosphere.
Carrier waves
Radio waves that are altered in a precise way so that they contain an audio signal.
