P6-Waves KW Flashcards
Amplitude
The maximum displacement of a wave from its undisturbed (equilibrium) position.
Angle of Incidence
The angle between the incident ray and normal
Angle of Reflection
The angle between the reflected ray and normal.
Black
An object will appear black if it absorbs all wavelengths of radiation incident on it
Colour Filters
Filters that absorb certain wavelengths (colours) and transmit others. A blue filter for example will absorb all wavelengths other than those in the blue region of the colour spectrum.
Colour
Colour is determined by frequency and wavelength.
Constant Temperature (H)
A body remains at a constant temperature if it is absorbing radiation at the same rate that it is emitting it. (H)
Convex Lens
A lens that brings parallel rays to focus at the principal focus.The image formed can be either real or virtual.
Diffuse Reflection
Reflection from a rough surface that results in scattering
Echo Sounding (H)
A technique that uses high frequency sound waves to detect objects in deep water and to measure the depth of water. (H)
Electromagnetic Waves
Transverse waves that transfer energy from the source of the waves, to an absorber. They form a continuous spectrum of different frequencies and all travel at the same speed in a vacuum.
Focal Length
The distance between the centre of a lens and its principal focus
Frequency
The number of waves passing a given point in a second. It is the inverse of the wave’s period
Hertz
The unit of frequency
Human Hearing (H)
Humans can hear sounds in the frequency range of 20Hz to 20kHz (H)
Infrared Radiation
A type of radiation that all objects emit and absorb. The hotter an object is, the greater the infrared radiation it emits in a given time.
Infrared
Used for cooking food, electrical heaters and infrared imaging.
Ionising Radiation
Radiation that can cause the mutation of genes and cause cancer. X-rays and gamma rays are both forms of ionising radiation
Magnification
The ratio of the image height over the object height for a lens. Since it is a ratio, it has no units.
Lens
An object that forms an image through the refraction of light
Longitudinal Waves
Waves with oscillations that are parallel to the direction of travel/energy transfer.
Microwaves
Used for satellite communications and for cooking food
Perfect Black Body
An object that absorbs all radiation incident on it and does not reflect or transmit any type of radiation
Normal
The normal is an imaginary reference line that is constructed perpendicular to a boundary at the point that the wave intercepts it.
P-Waves (H)
Longitudinal, seismic waves that travel at different speeds through solids and liquids. (H)
Period
The time it takes for one complete wave to pass a given point. It is the inverse of frequency
Radiation Dose
A measure of the risk of harm to the body as a result of radiation exposure
Reflection
Reflection is when a wave bounces off a boundary. The angle of incidence always equals the angle of reflection
Radio Waves
Used for television and radio signals. They can be produced by oscillations in electrical circuits.
S-Waves (H)
Transverse, seismic waves that cannot travel through liquids (H)
Seismic Waves (H)
Waves that are produced by earthquakes. (H)
Sound Waves (H)
The longitudinal waves responsible for sound. In solids, sound waves are transmitted by the vibrations of the solid’s particles. (H)
Specular Reflection
Reflection from a smooth surface, in a single direction
Ultrasound Scanning (H)
A technique that involves ultrasound waves being transmitted and then partially reflected at a boundary before being detected by a detector. The time between transmission and detection can be used to calculate distances, and build up an image (H)
Visible Light
The only type of electromagnetic radiation that our eyes can detect. It is used for fibre optic communications.
Ultrasound Waves (H)
Waves that have a frequency higher than the upper limit of
human hearing (20kHz). (H)
Transverse Waves
Waves with oscillations that are perpendicular to the direction of travel/energy transfer
Ultraviolet
Used in energy efficient lamps and for sun tanning.
Wave Speed
The speed at which energy is transferred through the medium. It is equal to the product of the wave’s wavelength and frequency
Wavelength
The distance from a point on one wave to the same point on the adjacent wave (ie. peak to peak or trough to trough)
White
An object will appear white if it emits all wavelengths equally.